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Cited by 1Microtubule and mitosis dynamicsCancer Treatment and PharmacologyProtein Kinase Regulation and GTPase Signaling

Taxane-induced conformational changes in the microtubule lattice activate GEF-H1-dependent RhoA signalling

Open access
Meiring, Joyce C. M., Mahapatra, Varsha, Liu, Ruijie, Gravett, Molly S. C., Morren, Daan, Saunders, Harriet A. J., Choi, Sung Ryul, Pelster José, Andressa +15 more·2026·Nature Cell Biology
DOI 10.1038/s41556-026-02079-4
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Abstract

Abstract Taxanes are widely used chemotherapeutic agents that perturb cell division. They also exert effects during interphase, but the underlying mechanisms are poorly understood. Here we show that taxanes activate RhoA signalling and induce actin remodelling by releasing the RhoA activator GEF-H1 from microtubules. This taxane-induced release of GEF-H1 occurs rapidly, is independent of tubulin post-translational modifications, and can be recapitulated using purified proteins. In vitro reconstitution assays combined with analyses of microtubule structure revealed that microtubule binding by GEF-H1 is inhibited by microtubule-stabilizing ligands that expand the microtubule lattice, such as taxanes and GMPCPP, but not by others, including GTPγS and discodermolide, which stabilize a compacted microtubule lattice. Our findings demonstrate that alterations in microtubule lattice conformation can activate key signalling pathways, offering insights into the mode of action of taxanes and the possible origins of their side effects.

AI snapshot

Written from the paper’s full text.

TL;DR

Taxanes rapidly activate RhoA signalling by releasing GEF-H1 from microtubules, and this release is driven by taxane-induced expansion of the microtubule lattice rather than by changes in microtubule dynamics or tubulin post-translational modifications. Discodermolide, which stabilizes microtubules without expanding the lattice, does not trigger GEF-H1 release or RhoA activation.

Key findings

  • Paclitaxel (10 µM) activated RhoA in serum-starved HT1080 cells, though more weakly than nocodazole (10 µM); docetaxel activated RhoA at 100 nM, and both effects were largely suppressed in GEF-H1 knockout cells. Discodermolide did not induce RhoA activation.
  • Paclitaxel caused GEF-H1-dependent actin remodelling, including stress fibre formation, cell rounding/blebbing, and increased phosphorylated myosin light chain; these effects were absent in GEF-H1 knockout cells and were not induced by discodermolide.
  • GFP-GEF-H1 dissociated from microtubules within 1 min of paclitaxel addition, but not after discodermolide; this was independent of tubulin acetylation or detyrosination, as tubacin, αTAT1, VASH2-SVBP, or MATCAP did not inhibit GEF-H1 microtubule binding.
  • In vitro, 500 pM GFP-GEF-H1 and 3 nM GFP-GEF-H1₁₋₁₃₆-G4 bound dynamic GDP lattices but avoided GMPCPP seeds; 20 µM paclitaxel wash-in rapidly dissociated both proteins, whereas 200 nM discodermolide did not. Cryo-EM showed discodermolide-stabilized microtubules had compacted lattices (81.7-Å and 81.6-Å dimer rise for 13- and 14-protofilament microtubules, versus 81.9 Å and 81.7 Å for GTPγS), and 100 nM GEF-H1 compacted paclitaxel-expanded microtubules.

Methods

  • Cell biology: HT1080, U2OS, Swiss 3T3, MDA-MB-231, 1205Lu, and HEK293T cells; serum starvation; RhoA2G FRET sensor live imaging; RhoA G-LISA; immunofluorescence; western blotting; GEF-H1 knockout generation; live-cell imaging with paclitaxel, docetaxel, nocodazole, discodermolide, or DMSO.
  • In vitro reconstitution: TIRF microscopy with dynamic microtubules grown from GMPCPP-stabilized seeds; purified GFP-GEF-H1 and GFP-GEF-H1₁₋₁₃₆-G4; wash-in assays with 20 µM paclitaxel or 200 nM discodermolide; IRM to determine protofilament number; mass spectrometry for protein purity.
  • Structural analysis: cryo-EM and single-particle analysis of discodermolide-stabilized 13- and 14-protofilament microtubules; lattice parameters calculated from helical searches; statistical tests included Welch’s t-test, Mann-Whitney, and Wilcoxon matched-pairs tests.

Limitations

  • The paper states that sample sizes were limited by practical resource and time constraints, that outliers were excluded when most treatments fit a normal distribution, and that researchers were not blind to treatment groups.
  • The paper states that cell lines were not authenticated, though they were tested negative for mycoplasma and no commonly misidentified lines were used.
  • The text makes evident that the structural basis for how GEF-H1 binding promotes lattice compaction in paclitaxel-expanded microtubules remains unclear, and the authors note that further studies with longer GEF-H1 fragments and better-binding microtubules are needed.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1038/s41556-026-02079-4

Cites

101 of 101 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

83 of 106 cited sources checked · 50 supported · 3 flagged · accuracy not yet measured

  • Interpretationcitation
    § Discussion · p. 9

    Local stabilization and expansion of microtubules near focal adhesions can potentially trigger GEF-H1 release and RhoA-dependent focal adhesion disassembly during cell movement.

    “Furthermore, local stabilization and expansion of microtubules in the vicinity of focal adhesions 32,74 can potentially trigger GEF-H1 release and RhoA-dependent focal adhesion disassembly during cell movement.”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [32] Seetharaman, S. et al. Microtubules tune mechanosensitive cell responses. Nat. Mater. 21, 366–377 https://doi.org/10.1038/s41563-021-01108-x (2022). source

      The paper reports that growing microtubule ends occur near focal adhesions in migrating cells, and that microtubule acetylation promotes GEF-H1 release and RhoA activation (sections labelled Abstract; pages unavailable). It also reports altered focal-adhesion dynamics, but does not establish that local microtubule stabilization and expansion trigger RhoA-dependent focal-adhesion disassembly. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [74] Stehbens, S. & Wittmann, T. Targeting and transport: how microtubules control focal adhesion dynamics. J. Cell Biol. 198, 481–489 https://doi.org/10.1083/jcb.201206050 (2012). source

      In “Microtubules modulate Rho GTPase signaling,” the paper says growing microtubules would be expected to sequester GEF-H1, decreasing rather than triggering RhoA activity; it also says a direct link between GEF-H1 and local microtubule-induced focal adhesion disassembly has not been established. In “Microtubule-mediated transport from and to FAs,” it reports that disassembly induced by microtubule regrowth is independent of RhoA activity. (LLM, conf=0.88)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
  • Findingown data
    § Paclitaxel induces the release of GEF-H1 from microtubules in cells · p. 5

    GFP-GEF-H1 avoided microtubules labelled with the marker for stable expanded microtubules, StableMARK.

    “Similarly, GFP-GEF-H1 avoided microtubules labelled with the marker for stable expanded microtubules, StableMARK 39,53 (Extended Data Fig. 3c).”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [39] de Jager, L. et al. StableMARK-decorated microtubules in cells have expanded lattices. J. Cell Biol. 224, e202206143 https://doi.org/10.1083/jcb.202206143 (2025). source
    • cites [53] Jansen, K. I., Iwanski, M. K., Burute, M. & Kapitein, L. C. A live-cell marker to visualize the dynamics of stable microtubules throughout the cell cycle. J. Cell Biol. 222, e202106105 https://doi.org/10.1083/jcb.202106105 (2023). source
  • Findingown data
    § Paclitaxel induces the release of GEF-H1 from microtubules in cells · p. 5

    GFP-GEF-H1 was barely detected on acetylated microtubules in U2OS cells.

    “but was barely detected on acetylated microtubules (Fig. 3a, yellow dashed line, and Fig. 3c)”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [32] Seetharaman, S. et al. Microtubules tune mechanosensitive cell responses. Nat. Mater. 21, 366–377 https://doi.org/10.1038/s41563-021-01108-x (2022). source

      The passage labeled Abstract (page unavailable) says microtubule acetylation promotes GEF-H1 release from microtubules, supporting the direction of the claim. It reports GEF-H1 localization in astrocytes, however, not barely detectable GFP-GEF-H1 on acetylated microtubules in U2OS cells; searches for those specific terms found no such result. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [33] Deb Roy, A. et al. OptoTAT reveals microtubule acetylation as a rapid trigger for GEF-H1–mediated cell migration. J. Cell Biol. 225, e202508095 https://doi.org/10.1083/jcb.202508095 (2026). source

      The Results section, under “Microtubule acetylation releases GEF-H1 from sequestration” (page unavailable), reports a negative spatial correlation between microtubule-bound GEF-H1 and acetylated microtubules. That observation was made by immunostaining WT mouse embryonic fibroblasts, not by detecting GFP-GEF-H1 in U2OS cells; the cited paper therefore supports the general localization pattern but not the specified cell type or fluorescent construct. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
  • Findingcitation
    § Paclitaxel induces the release of GEF-H1 from microtubules in cells · p. 5

    Discodermolide efficiently inhibits microtubule elongation, as detected by staining of EB1/EB3-positive microtubule plus ends.

    “discodermolide 45,46 , which also efficiently inhibits microtubule elongation, as detected by staining of EB1/EB3 positive microtubule plus ends (Extended Data Fig. 3d)”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [45] Longley, R. E., Caddigan, D., Harmody, D., Gunasekera, M. & Gunasekera, S. P. Discodermolide—a new, marine-derived immunosuppressive compound. I. In vitro studies. Transplantation 52, 650–656 https://doi.org/10.1097/00007890-199110000-00014 (1991). source
    • cites [46] Buey, R. M. et al. Microtubule interactions with chemically diverse stabilizing agents: thermodynamics of binding to the paclitaxel site predicts cytotoxicity. Chem. Biol. 12, 1269–1279 https://doi.org/10.1016/j.chembiol.2005.09.010 (2005). source
  • Premisecitation
    § Fig. 1 | Paclitaxel activates RhoA in cells in a GEF-H1 dependent manner. · p. 2

    Docetaxel has a higher affinity to microtubules than paclitaxel.

    “Importantly, docetaxel, a taxane with a higher affinity to microtubules 46 , and which is often used for cancer chemotherapy 49 , could activate RhoA signalling at a concentration of even 100 nM (Fig. 1f).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [46] Buey, R. M. et al. Microtubule interactions with chemically diverse stabilizing agents: thermodynamics of binding to the paclitaxel site predicts cytotoxicity. Chem. Biol. 12, 1269–1279 https://doi.org/10.1016/j.chembiol.2005.09.010 (2005). source
  • Classified as probably not a substantial claim. 48
  • May combine two claims. 37
  • The quote only partly states this claim. 1

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationcitation
    § Discussion · p. 9

    The ability of taxanes to activate RhoA can be relevant for understanding their efficacy in cancer therapy, because RhoA can promote anti-tumour immune responses.

    “The ability of taxanes to activate RhoA can be relevant for understanding their efficacy in cancer therapy, because RhoA can promote anti-tumour immune responses 19,75,76 .”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites [19] Kashyap, A. S. et al. GEF-H1 signaling upon microtubule destabilization is required for dendritic cell activation and specific anti-tumor responses. Cell Rep. 28, 3367–3380 https://doi.org/10.1016/j.celrep.2019.08.057 (2019). source

      The Results (page unavailable) report that the taxanes paclitaxel and docetaxel had no dendritic-cell-stimulatory effects. The Discussion (page unavailable) says the GEF-H1 immune pathway studied is specific to microtubule-destabilizing drugs and is not used by those taxanes. Although it mentions RhoA as a downstream substrate of GEF-H1, it does not establish the proposed taxane–RhoA route to anti-tumour immunity. (LLM, conf=0.86)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
    • cites [75] Bros, M., Haas, K., Moll, L. & Grabbe, S. RhoA as a key regulator of innate and adaptive immunity. Cells 8, 733 https://doi.org/10.3390/cells8070733 (2019). source

      Section 3.2 describes RhoA’s role in T-cell activation and migration, supporting the general point that RhoA can facilitate immune responses. Section 3.1 mentions anti-tumour immune responses, but does not establish that RhoA promotes them; the paper also does not link taxane-induced RhoA activation to cancer-treatment efficacy. The taxane-activation point may be covered by the sentence’s other citations. (LLM, conf=0.80)

      Experimental — accuracy not yet measured
    • cites [76] Kalim, K. W. et al. Graded RhoA GTPase expression in Treg cells distinguishes tumor immunity from autoimmunity. Front. Immunol. 12, 726393 https://doi.org/10.3389/fimmu.2021.726393 (2021). source

      The Results (page unavailable) report that reducing RhoA expression in regulatory T cells triggered anti-tumour T-cell immunity and suppressed tumour growth—the opposite direction from the claim that activating RhoA promotes that response. The paper does not discuss taxanes. (LLM, conf=0.90)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured

  • Classified as probably not a substantial claim.

    Premisecitation
    § Paclitaxel induces the release of GEF-H1 from microtubules in cells · p. 5

    Full-length GEF-H1 is a coiled-coil dimer.

    “Because full-length GEF-H1 is a coiled-coil dimer 22”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [22] Choi, S. R. et al. Structural basis of microtubule-mediated signal transduction. Cell 189, 461–477 https://doi.org/10.1016/j.cell.2025.11.011 (2026). source

  • May combine two claims.

    Findingown data
    § Paclitaxel induces the release of GEF-H1 from microtubules in cells · p. 5

    Induction of microtubule detyrosination by overexpressing VASH2-SVBP or MATCAP either did not impact the localization of GEF-H1 to microtubules or showed a slight increase in binding.

    “Induction of microtubule detyrosination (removal of the C-terminal tyrosine of α-tubulin), another modification associated with microtubule stability 31 , by overexpressing the detyrosinating enzymes VASH2-SVBP or MATCAP 56-58 , either did not impact the localization of GEF-H1 to microtubules or showed a slight increase in binding (Extended Data Fig. 4b-e).”
    Quote in the paperSubstantial claim3 of 4 sources checked
    • cites [31] Magiera, M. M., Singh, P., Gadadhar, S. & Janke, C. Tubulin posttranslational modifications and emerging links to human disease. Cell 173, 1323–1327 https://doi.org/10.1016/j.cell.2018.05.018 (2018). source

      The indexed passage on detyrosination (section labeled Abstract; page unavailable) says that vasohibins catalyze tubulin detyrosination and cites work identifying vasohibins/SVBP as tubulin carboxypeptidases. It does not report VASH2-SVBP or MATCAP overexpression experiments, or whether detyrosination changes GEF-H1 localization or binding to microtubules; those results are attributed to the citing paper’s Extended Data Fig. 4b–e. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [56] Aillaud, C. et al. Vasohibins/SVBP are tubulin carboxypeptidases (TCPs) that regulate neuron differentiation. Science 358, 1448–1453 https://doi.org/10.1126/science.aao4165 (2017). source
    • cites [57] Nieuwenhuis, J. et al. Vasohibins encode tubulin detyrosinating activity. Science 358, 1453–1456 https://doi.org/10.1126/science.aao5676 (2017). source
    • cites [58] Landskron, L. et al. Posttranslational modification of microtubules by the MATCAP detyrosinase. Science 376, eabn6020 https://doi.org/10.1126/science.abn6020 (2022). source

  • Classified as probably not a substantial claim.

    Premisecitation
    § Taxane-induced conformational changes in the microtubule lattice activate GEF-H1-dependent RhoA signalling · p. 2

    RhoA activation is primarily restricted to the plasma membrane.

    “Sequestration of GEF-H1 on microtubules can effectively regulate its activity, because RhoA activation is primarily restricted to the plasma membrane 30 .”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [30] de Seze, J., Gatin, J. & Coppey, M. RhoA regulation in space and time. FEBS Lett. 597, 836–849 https://doi.org/10.1002/1873-3468.14578 (2023). source

      The Conclusions and perspectives section (Fig. 7; page not specified in our copy) says active RhoA preferentially binds the plasma membrane and has its highest potential to activate downstream pathways there. But the same section says RhoA can be GTP-bound in both the cytoplasm and at the membrane, so describing its activation as primarily restricted to the membrane overstates the spatial restriction. (LLM, conf=0.87)

      Experimental — accuracy not yet measured

  • Classified as probably not a substantial claim.

    Premisecitation
    § Taxane-induced conformational changes in the microtubule lattice activate GEF-H1-dependent RhoA signalling · p. 2

    Acetylation in interphase cells typically occurs on stable microtubules.

    “Acetylation in interphase cells typically occurs on stable microtubules 37,38 , and stable microtubules were recently found to have a distinct, expanded lattice conformation 39 .”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [37] Piperno, G., LeDizet, M. & Chang, X. J. Microtubules containing acetylated alpha-tubulin in mammalian cells in culture. J. Cell Biol. 104, 289–302 https://doi.org/10.1083/jcb.104.2.289 (1987). source
    • cites [38] Cambray-Deakin, M. A. & Burgoyne, R. D. Acetylated and detyrosinated alpha-tubulins are co-localized in stable microtubules in rat meningeal fibroblasts. Cell Motil. Cytoskeleton 8, 284–291 https://doi.org/10.1002/cm.970080309 (1987). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Fig. 2 | Paclitaxel activates downstream effectors of RhoA in a GEF-H1- · p. 5

    Phosphorylated myosin light chain (p-MLC) is a downstream target of RhoA signalling.

    “myosin light chain (p-MLC), a downstream target of RhoA signalling 51”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [51] Lawson, C. D. & Ridley, A. J. Rho GTPase signaling complexes in cell migration and invasion. J. Cell Biol. 217, 447–457 https://doi.org/10.1083/jcb.201612069 (2018). source

      The Rho-specific GEF complexes section says that GEF-H1 activates RHOA to increase actomyosin contractility. That supports a downstream effect of RhoA signalling, but our copy does not identify phosphorylated myosin light chain (p-MLC) as that downstream target; searches for “myosin light chain” and “MLC phosphorylation” did not find it. (LLM, conf=0.76)

      Experimental — accuracy not yet measured

  • Classified as probably not a substantial claim.

    Premisecitation
    § Paclitaxel induces the release of GEF-H1 from microtubules in cells · p. 5

    Microtubule-destabilizing agents activate GEF-H1 by inducing its unbinding from microtubules.

    “As microtubule-destabilizing agents activate GEF-H1 by inducing its unbinding from microtubules 18-21”
    Quote in the paperSubstantial claim2 of 4 sources checked
    • cites [18] Krendel, M., Zenke, F. T. & Bokoch, G. M. Nucleotide exchange factor GEF-H1 mediates cross-talk between microtubules and the actin cytoskeleton. Nat. Cell Biol. 4, 294–301 (2002). source
    • cites [19] Kashyap, A. S. et al. GEF-H1 signaling upon microtubule destabilization is required for dendritic cell activation and specific anti-tumor responses. Cell Rep. 28, 3367–3380 https://doi.org/10.1016/j.celrep.2019.08.057 (2019). source
    • cites [20] Birkenfeld, J., Nalbant, P., Yoon, S. H. & Bokoch, G. M. Cellular functions of GEF-H1, a microtubule-regulated Rho-GEF: is altered GEF-H1 activity a crucial determinant of disease pathogenesis? Trends Cell Biol. 18, 210–219 https://doi.org/10.1016/j.tcb.2008.02.006 (2008). source
    • cites [21] Azoitei, M. L. et al. Spatiotemporal dynamics of GEF-H1 activation controlled by microtubule- and Src-mediated pathways. J. Cell Biol. 218, 3077–3097 https://doi.org/10.1083/jcb.201812073 (2019). source

  • May combine two claims.

    Premisecitation
    § Taxane-induced conformational changes in the microtubule lattice activate GEF-H1-dependent RhoA signalling · p. 1

    GEF-H1 is sequestered on microtubules in an inactive form and becomes active upon release from microtubules.

    “This effect depends on the RhoA activator guanine nucleotide exchange factor H1 (GEF-H1), which is sequestered on microtubules in an inactive form, but becomes active upon release from microtubules 18-22 .”
    Quote in the paperSubstantial claim3 of 5 sources checked
    • cites [18] Krendel, M., Zenke, F. T. & Bokoch, G. M. Nucleotide exchange factor GEF-H1 mediates cross-talk between microtubules and the actin cytoskeleton. Nat. Cell Biol. 4, 294–301 (2002). source
    • cites [19] Kashyap, A. S. et al. GEF-H1 signaling upon microtubule destabilization is required for dendritic cell activation and specific anti-tumor responses. Cell Rep. 28, 3367–3380 https://doi.org/10.1016/j.celrep.2019.08.057 (2019). source
    • cites [20] Birkenfeld, J., Nalbant, P., Yoon, S. H. & Bokoch, G. M. Cellular functions of GEF-H1, a microtubule-regulated Rho-GEF: is altered GEF-H1 activity a crucial determinant of disease pathogenesis? Trends Cell Biol. 18, 210–219 https://doi.org/10.1016/j.tcb.2008.02.006 (2008). source
    • cites [21] Azoitei, M. L. et al. Spatiotemporal dynamics of GEF-H1 activation controlled by microtubule- and Src-mediated pathways. J. Cell Biol. 218, 3077–3097 https://doi.org/10.1083/jcb.201812073 (2019). source
    • cites [22] Choi, S. R. et al. Structural basis of microtubule-mediated signal transduction. Cell 189, 461–477 https://doi.org/10.1016/j.cell.2025.11.011 (2026). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Taxane-induced conformational changes in the microtubule lattice activate GEF-H1-dependent RhoA signalling · p. 2

    Acetylation occurs on the luminal microtubule surface.

    “The underlying mechanism is likely to be indirect, because GEF-H1 binds to the outer microtubule surface 22 , whereas acetylation occurs on the luminal microtubule surface 34-36 .”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites [34] Howes, S. C., Alushin, G. M., Shida, T., Nachury, M. V. & Nogales, E. Effects of tubulin acetylation and tubulin acetyltransferase binding on microtubule structure. Mol. Biol. Cell 25, 257–266 https://doi.org/10.1091/mbc.E13-07-0387 (2014). source
    • cites [35] Luo, J. et al. Tubulin acetyltransferases access and modify the microtubule luminal K40 residue through anchors in taxane-binding pockets. Nat. Struct. Mol. Biol. 32, 358–368 https://doi.org/10.1038/s41594-024-01406-3 (2025). source
    • cites [36] Iuzzolino, A., Pellegrini, F. R., Rotili, D., Degrassi, F. & Trisciuoglio, D. The alpha-tubulin acetyltransferase ATAT1: structure, cellular functions, and its emerging role in human diseases. Cell. Mol. Life Sci. 81, 193 https://doi.org/10.1007/s00018-024-05227-x (2024). source

  • Classified as probably not a substantial claim.

    Premisecitation
    § Taxane-induced conformational changes in the microtubule lattice activate GEF-H1-dependent RhoA signalling · p. 2

    GEF-H1 avoids acetylated microtubules.

    “Previous studies have suggested that GEF-H1 avoids acetylated microtubules 32,33 .”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [32] Seetharaman, S. et al. Microtubules tune mechanosensitive cell responses. Nat. Mater. 21, 366–377 https://doi.org/10.1038/s41563-021-01108-x (2022). source
    • cites [33] Deb Roy, A. et al. OptoTAT reveals microtubule acetylation as a rapid trigger for GEF-H1–mediated cell migration. J. Cell Biol. 225, e202508095 https://doi.org/10.1083/jcb.202508095 (2026). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Taxane-induced conformational changes in the microtubule lattice activate GEF-H1-dependent RhoA signalling · p. 2

    Microtubule stabilization can potentially affect microtubule-associated components of signalling cascades by altering their turnover and tubulin post-translational modifications.

    “However, microtubule stabilization can potentially affect microtubule-associated components of signalling cascades by altering their turnover and tubulin post-translational modifications 31 .”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [31] Magiera, M. M., Singh, P., Gadadhar, S. & Janke, C. Tubulin posttranslational modifications and emerging links to human disease. Cell 173, 1323–1327 https://doi.org/10.1016/j.cell.2018.05.018 (2018). source

      The passage beginning “In living cells” (indexed as Abstract; no page supplied) says tubulin post-translational modifications can affect microtubule stability and interactions with microtubule-associated proteins. It does not say that stabilizing microtubules alters their turnover or modifications, or that this affects components of signalling cascades. (LLM, conf=0.78)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Paclitaxel causes GEF-H1-dependent actin remodelling · p. 2

    Y-27632 is an inhibitor of Rho-associated protein kinase (ROCK), a kinase acting downstream of RhoA.

    “Treatment with Y-27632, an inhibitor of Rho-associated protein kinase (ROCK), a kinase acting downstream of RhoA 50-52 , had no strong effect on actin organization or cell shape in these conditions (Fig. 2a,c,e and Extended Data Fig. 2a-f), in agreement with serum starvation reducing the baseline RhoA activity.”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites [50] Amano, M., Nakayama, M. & Kaibuchi, K. Rho-kinase/ROCK: a key regulator of the cytoskeleton and cell polarity. Cytoskeleton (Hoboken) 67, 545–554 https://doi.org/10.1002/cm.20472 (2010). source
    • cites [51] Lawson, C. D. & Ridley, A. J. Rho GTPase signaling complexes in cell migration and invasion. J. Cell Biol. 217, 447–457 https://doi.org/10.1083/jcb.201612069 (2018). source

      The Rho-specific GEF complexes section identifies ROCK as a RHOA effector, supporting the downstream relationship. Our copy does not identify Y-27632 as a ROCK inhibitor (searched: “Y-27632” and “Y-27632 inhibitor of ROCK”). The citing paper’s observation about actin organization and cell shape is not part of the claim attributed to this source. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [52] Riento, K. & Ridley, A. J. Rocks: multifunctional kinases in cell behaviour. Nat. Rev. Mol. Cell Biol. 4, 446–456 https://doi.org/10.1038/nrm1128 (2003). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation
    § Discussion · p. 7

    Lattice conformation is emerging as an important, understudied constituent of the 'tubulin code'.

    “Next to microtubule post-translational modifications and tubulin isotypes, lattice conformation is emerging as an important, understudied constituent of the 'tubulin code', the structural, biochemical and functional diversification of microtubule subsets in the same cell 68-70 .”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites [68] Janke, C. & Magiera, M. M. The tubulin code and its role in controlling microtubule properties and functions. Nat. Rev. Mol. Cell Biol. 21, 307–326 https://doi.org/10.1038/s41580-020-0214-3 (2020). source
    • cites [69] Verhey, K. J. & Ohi, R. Causes, costs and consequences of kinesin motors communicating through the microtubule lattice. J. Cell Sci. 136, jcs260735 https://doi.org/10.1242/jcs.260735 (2023). source
    • cites [70] Akhmanova, A. & Kapitein, L. C. Mechanisms of microtubule organization in differentiated animal cells. Nat. Rev. Mol. Cell Biol. 23, 541–558 https://doi.org/10.1038/s41580-022-00473-y (2022). source

  • May combine two claims.

    Premisecitation
    § Discussion · p. 9

    Acetylated, stable microtubules have expanded lattices, making them more similar in conformation to paclitaxel- and GMPCPP-stabilized microtubules.

    “probably because their lattices are expanded 39,53 and are thus more similar in conformation to paclitaxel- and GMPCPP-stabilized microtubules.”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [39] de Jager, L. et al. StableMARK-decorated microtubules in cells have expanded lattices. J. Cell Biol. 224, e202206143 https://doi.org/10.1083/jcb.202206143 (2025). source

      The Results and discussion report that StableMARK-marked stable microtubules have expanded lattices resembling those of Taxol (paclitaxel)- and GMPCPP-stabilized microtubules. The paper says this marked subset is often highly acetylated, but it does not establish that acetylated microtubules generally have expanded lattices or that acetylation causes the expansion. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [53] Jansen, K. I., Iwanski, M. K., Burute, M. & Kapitein, L. C. A live-cell marker to visualize the dynamics of stable microtubules throughout the cell cycle. J. Cell Biol. 222, e202106105 https://doi.org/10.1083/jcb.202106105 (2023). source

  • May combine two claims.

    Findingown data
    § Discussion · p. 9

    Discodermolide stabilizes compacted microtubule lattices, unlike taxanes.

    “Cryo-EM data showed that, unlike taxanes, discodermolide stabilizes compacted microtubule lattices; this is in line with recent analysis based on fibre diffraction 41 .”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [41] Lucena-Agell, D. et al. An atlas of microtubule lattice parameters regulated through ligand binding to the microtubule-stabilizing sites. Proc. Natl Acad. Sci. USA 123, e2532791123 https://doi.org/10.1073/pnas.2532791123 (2026). source

      Table 1 (p. 4) classifies discodermolide-treated microtubules as having a compact lattice, while paclitaxel-treated microtubules have an expanded lattice. But the Discussion (p. 9) says lattice expansion is not universal among taxane-site ligands: chemical modifications of paclitaxel can switch the preferred state. The unqualified contrast with taxanes therefore overstates the finding. (LLM, conf=0.84)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationreasoning
    § Discussion · p. 9

    GEF-H1 can control RhoA activity in response to local changes in the density of dynamic microtubules near the cell margin, e.g., to promote cell invasion or trigger cell retraction and help migrating dendritic cells maintain coherence.

    “In this way, GEF-H1 can control RhoA activity in response to local changes in the density of dynamic microtubules near the cell margin, for example, to promote cell invasion into a dense matrix or trigger cell retraction and help cells with long and elaborate protrusions, such as migrating dendritic cells, to maintain their coherence 21,24-26 .”
    Quote in the paperSubstantial claim3 of 4 sources checked
    • cites [21] Azoitei, M. L. et al. Spatiotemporal dynamics of GEF-H1 activation controlled by microtubule- and Src-mediated pathways. J. Cell Biol. 218, 3077–3097 https://doi.org/10.1083/jcb.201812073 (2019). source

      The Discussion (page not provided) says local microtubule disassembly increases GEF-H1 activity, while the Results link GEF-H1 and RhoA activity to cell-edge retraction in migrating MDA-MB-231 cells. Our copy does not establish that this mechanism promotes invasion into a dense matrix or helps migrating dendritic cells maintain coherence. (LLM, conf=0.87)

      Experimental — accuracy not yet measured
    • cites [24] Heck, J. N. et al. Microtubules regulate GEF-H1 in response to extracellular matrix stiffness. Mol. Biol. Cell 23, 2583–2592 https://doi.org/10.1091/mbc.E11-10-0876 (2012). source

      The Introduction and Results report that microtubules participate in GEF-H1–dependent RhoA activation in response to matrix stiffness, and that GEF-H1 knockdown inhibits breast carcinoma cell invasion through stiff gels. The paper does not establish that local changes in dynamic microtubule density near the cell margin trigger retraction or help migrating dendritic cells maintain coherence (no page numbers are available in our copy). (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [25] Nalbant, P., Chang, Y. C., Birkenfeld, J., Chang, Z. F. & Bokoch, G. M. Guanine nucleotide exchange factor-H1 regulates cell migration via localized activation of RhoA at the leading edge. Mol. Biol. Cell 20, 4070–4082 https://doi.org/10.1091/mbc.e09-01-0041 (2009). source
    • cites [26] Kopf, A. et al. Microtubules control cellular shape and coherence in amoeboid migrating cells. J. Cell Biol. 219, e201907154 https://doi.org/10.1083/jcb.201907154 (2020). source
    • Rests on an assumption: Endogenous GEF-H1 is present at levels sufficient to detect but not to alter microtubule lattice compaction.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Characterization of GEF-H1-microtubule interactions by in vitro reconstitution assays · p. 7

    In mammalian cells, the majority of microtubules consist of 13 protofilaments.

    “In mammalian cells the majority of microtubules consist of 13 protofilaments 63 , so these data suggest that the GEF-H1-microtubule interaction is not particularly sensitive to protofilament number.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [63] Chaaban, S. & Brouhard, G. J. A microtubule bestiary: structural diversity in tubulin polymers. Mol. Biol. Cell 28, 2924–2931 https://doi.org/10.1091/mbc.E16-05-0271 (2017). source

  • May combine two claims.

    Interpretationcitation
    § Discussion · p. 9

    When strongly overexpressed, GEF-H1 can induce its preferred lattice conformation, which cannot be altered by paclitaxel.

    “This explains why the sensitivity of GEF-H1 to taxanes has been overlooked previously 19 : when strongly overexpressed, GEF-H1 can induce its preferred lattice conformation, which cannot be altered by paclitaxel.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [19] Kashyap, A. S. et al. GEF-H1 signaling upon microtubule destabilization is required for dendritic cell activation and specific anti-tumor responses. Cell Rep. 28, 3367–3380 https://doi.org/10.1016/j.celrep.2019.08.057 (2019). source

      The Results section ('Microtubule Destabilization by MDAs Releases and Activates GEF-H1'; page not provided) reports that taxane did not release GEF-H1 from microtubules in cells overexpressing GEF-H1-GFP. It does not say that strong overexpression induces a preferred lattice conformation or that paclitaxel cannot alter that conformation. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • Rests on an assumption: Endogenous GEF-H1 is present at levels sufficient to detect but not to alter microtubule lattice compaction.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation
    § Discussion · p. 9

    Misregulation of RhoA might contribute to side effects of taxanes, such as neuropathy.

    “On the other hand, misregulation of RhoA might contribute to the side effects of taxanes, such as neuropathy 82,83 .”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [82] McCray, B. A. et al. Neuropathy-causing TRPV4 mutations disrupt TRPV4-RhoA interactions and impair neurite extension. Nat. Commun. 12, 1444 https://doi.org/10.1038/s41467-021-21699-y (2021). source

      The Results section on TRPV4–RhoA interactions links excessive RhoA activity to neuropathy caused by TRPV4 mutations. It does not address taxanes or establish that RhoA misregulation contributes to their side effects (searched: taxanes, paclitaxel, docetaxel). (LLM, conf=0.87)

      Experimental — accuracy not yet measured
    • cites [83] Ohsawa, M., Aasato, M., Hayashi, S. S. & Kamei, J. RhoA/Rho kinase pathway contributes to the pathogenesis of thermal hyperalgesia in diabetic mice. Pain 152, 114–122 https://doi.org/10.1016/j.pain.2010.10.005 (2011). source

  • Classified as probably not a substantial claim.

    Premisecitation
    § Discussion · p. 7

    Diversity of microtubule conformations includes differences in protofilament number, longitudinal compaction or expansion, and dimer twist.

    “Diversity of microtubule conformations includes differences in protofilament number, longitudinal compaction or expansion, and dimer twist 63,66,71,72 (Extended Data Fig. 6c).”
    Quote in the paperSubstantial claim4 of 4 sources checked
    • cites [63] Chaaban, S. & Brouhard, G. J. A microtubule bestiary: structural diversity in tubulin polymers. Mol. Biol. Cell 28, 2924–2931 https://doi.org/10.1091/mbc.E16-05-0271 (2017). source

      The Introduction and Figure 1 describe variation in protofilament number, supporting that part of the claim. They also describe protofilament supertwist in non–13-protofilament microtubules, but do not establish variation in longitudinal compaction or expansion or in dimer twist. Page numbers are unavailable in our copy. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [66] Kellogg, E. H. et al. Insights into the distinct mechanisms of action of taxane and non-taxane microtubule stabilizers from cryo-EM structures. J. Mol. Biol. 429, 633–646 https://doi.org/10.1016/j.jmb.2017.01.001 (2017). source
    • cites [71] Paquette, A. L. et al. Competition for microtubule lattice spacing between a microtubule expander and compactor. Curr. Biol. 35, 4442–4452 e4444 https://doi.org/10.1016/j.cub.2025.07.080 (2025). source

      The Abstract states that microtubules have expanded and compacted states defined by αβ-tubulin dimer lattice spacing. The passages from our copy do not address variation in protofilament number or dimer twist (searched both terms), so they support only the longitudinal-spacing part of the attributed claim. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [72] LaFrance, B. J. et al. Structural transitions in the GTP cap visualized by cryo-electron microscopy of catalytically inactive microtubules. Proc. Natl Acad. Sci. USA 119, e2114994119 https://doi.org/10.1073/pnas.2114994119 (2022). source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationcitation
    § Discussion · p. 9

    RhoA signalling might potentially contribute to cell death, because it can promote apoptosis in low-adhesion environments by increasing cell contractility.

    “RhoA signalling might also potentially contribute to cell death, because it can promote apoptosis in low-adhesion environments by increasing cell contractility, explaining why ROCK inhibitors are a standard component of media for stem cells and organoid isolation and maintenance in culture 77-81 .”
    Quote in the paperNot a substantial claim3 of 5 sources checked
    • cites [77] Martin-Ibanez, R. et al. Novel cryopreservation method for dissociated human embryonic stem cells in the presence of a ROCK inhibitor. Hum. Reprod. 23, 2744–2754 https://doi.org/10.1093/humrep/den316 (2008). source
    • cites [78] Sato, T. et al. Single Lgr5 stem cells build crypt-villus structures in vitro without a mesenchymal niche. Nature 459, 262–265 https://doi.org/10.1038/nature07935 (2009). source
    • cites [79] Koyanagi, M. et al. Inhibition of the Rho/ROCK pathway reduces apoptosis during transplantation of embryonic stem cell-derived neural precursors. J. Neurosci. Res. 86, 270–280 https://doi.org/10.1002/jnr.21502 (2008). source

      The paper summary (page not specified) reports that dispersing mouse embryonic stem cell–derived neural precursors activated Rho and led to cell death, which Rho and ROCK inhibitors reduced. The examination summary likewise links loss of cell adhesion to Rho/ROCK activity and apoptosis. Neither passage establishes increased cell contractility as the mechanism, or says ROCK inhibitors are standard components of stem-cell and organoid culture media. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [80] Minambres, R., Guasch, R. M., Perez-Arago, A. & Guerri, C. The RhoA/ROCK-I/MLC pathway is involved in the ethanol-induced apoptosis by anoikis in astrocytes. J. Cell Sci. 119, 271–282 https://doi.org/10.1242/jcs.02723 (2006). source
    • cites [81] Walker, A. et al. Non-muscle myosin II regulates survival threshold of pluripotent stem cells. Nat. Commun. 1, 71 https://doi.org/10.1038/ncomms1074 (2010). source

      The Abstract reports that inhibiting non-muscle myosin II improves pluripotent stem-cell survival under single-cell growth conditions, and the Results report improved survival in suspension culture. But the Discussion says RhoA’s role as an upstream regulator of myosin II in this cell death remains to be determined; the paper does not establish that RhoA promotes apoptosis by increasing contractility in low-adhesion environments. (LLM, conf=0.84)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation
    § Discussion · p. 9

    Proteins serving as 'conformational code readers' can become 'code writers' at a high concentration, an important feature of microtubule lattice plasticity.

    “An important feature of microtubule lattice plasticity, in contrast to biochemical modifications, is that proteins serving as 'conformational code readers' can become 'code writers' at a high concentration 73 .”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [73] Siahaan, V. et al. Microtubule lattice spacing governs cohesive envelope formation of tau family proteins. Nat. Chem. Biol. 18, 1224–1235 https://doi.org/10.1038/s41589-022-01096-2 (2022). source

  • May combine two claims.

    Findingown data
    § Paclitaxel causes GEF-H1-dependent actin remodelling · p. 2

    Discodermolide affects microtubule organization, inducing tightly curved microtubules in U2OS cells.

    “However, stabilization of microtubules by discodermolide did not induce any striking changes in F-actin organization nor cell morphology (Fig. 2a,c,e and Extended Data Fig. 2a-f), even though it did affect microtubule organization: for example, in U2OS cells, it induced tightly curved microtubules (Extended Data Fig. 2b(i,ii), blue arrowheads).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § Taxanes activate RhoA through GEF-H1 · p. 2

    In serum-starved HT1080 cells, RhoA activity is low and shows a rapid transient increase upon serum addition.

    “As expected, RhoA activity was low in serum-starved cells, but showed a rapid transient increase with serum addition (Fig. 1a,b).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § Paclitaxel causes GEF-H1-dependent actin remodelling · p. 2

    Microtubule disassembly with nocodazole induces formation of stress fibres, blebs and cell rounding.

    “In contrast, microtubule disassembly with nocodazole induced the formation of stress fibres, blebs and cell rounding (Fig. 2a,c,e and Extended Data Fig. 2a-f).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § Paclitaxel causes GEF-H1-dependent actin remodelling · p. 2

    In GEF-H1 knockout cells, MTA treatments had no pronounced effect on the actin cytoskeleton, and cells retained their elongated shape.

    “In GEF-H1 knockout cells, MTA treatments had no pronounced effect on the actin cytoskeleton, and cells retained their elongated shape (Fig. 2b,d,f).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Paclitaxel causes GEF-H1-dependent actin remodelling · p. 2

    Serum-starved HT1080, Swiss 3T3 and U2OS cells are elongated and have only a few stress fibres and lamellipodia at the leading edge.

    “Serum-starved HT1080, Swiss 3T3 and U2OS cells were elongated and had only a few stress fibres and lamellipodia at the leading edge (Fig. 2a and Extended Data Fig. 2a,b).”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Findingown data
    § Paclitaxel induces the release of GEF-H1 from microtubules in cells · p. 5

    GEF-H1 immunostaining in cells shows strong variability and ambiguous microtubule co-localization, making reliable quantitative analysis difficult.

    “GEF-H1 immunostaining in cells shows strong variability and ambiguous microtubule co-localization, making reliable quantitative analysis difficult (Extended Data Fig. 1d).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Paclitaxel induces the release of GEF-H1 from microtubules in cells · p. 5

    The GFP-GEF-H11-136-G4 construct is released from microtubules by paclitaxel but not by discodermolide.

    “The GFP-GEF-H11-136 -G4 construct was also released from microtubules by paclitaxel but not by discodermolide (Extended Data Fig. 3e).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Discussion · p. 7

    GEF-H1 binds well to 13-protofilament microtubules in cells and 14-protofilament microtubules in vitro.

    “Our data indicate that GEF-H1 binds well to 13-protofilament microtubules in cells and 14-protofilament microtubules in vitro.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data
    § Extended Data Fig. 6 | Comparison of microtubule lattice parameters. · p. 26

    The cryo-EM map of the discodermolide-stabilised 13-protofilament microtubule was determined at 3.47 Å resolution.

    “(f) Cryo-EM map of discodermolide stabilised 13 pf microtubule (3.47 Å). Contour level 0.05.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § Fig. 4 | Characterization of GEF-H1-microtubule interactions by in vitro · p. 7

    Both GFP-GEF-H1 and GFP-GEF-H11-136-G4 rapidly dissociate from microtubules after paclitaxel wash-in.

    “The binding of GFP-GEF-H1 and GFP-GEF-H11-136 -G4 to microtubules was not altered by discodermolide addition, but both proteins very rapidly dissociated after paclitaxel wash-in (Fig. 4j-o).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Discussion · p. 9

    Discodermolide inhibited microtubule growth in cells but did not trigger GEF-H1 detachment from microtubules, similar to paclitaxel.

    “Similar to paclitaxel, discodermolide inhibited microtubule growth in cells but did not trigger GEF-H1 detachment from microtubules.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Discussion · p. 9

    The GEF-H1 binding site on paclitaxel-stabilized microtubules is located close to the non-exchangeable nucleotide N-sites on the two adjacent α-tubulins and distant from the E-sites on the corresponding β-tubulins.

    “This binding site is located close to the non-exchangeable nucleotide N-sites on the two adjacent α-tubulins and is distant from the E-sites on the corresponding β-tubulins (Extended Data Fig. 6d).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data
    § Extended Data Fig. 6 | Comparison of microtubule lattice parameters. · p. 26

    The cryo-EM map of the discodermolide-stabilised 14-protofilament microtubule was determined at 2.73 Å resolution.

    “(g) Cryo-EM map of discodermolide stabilised 14 pf microtubule (2.73 Å). Contour level 0.07.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § Characterization of GEF-H1-microtubule interactions by in vitro reconstitution assays · p. 7

    Both GFP-GEF-H1 and GFP-GEF-H11-136-G4 efficiently accumulate on dynamic microtubule lattices at very low concentrations (500 pM for full-length GEF-H1 and 3 nM for GEF-H1 1-136-G4) but strongly avoid GMPCPP-stabilized seeds.

    “Both GFP-GEF-H1 and GFP-GEFH11-136 -G4 efficiently accumulated on dynamic microtubule lattices even at very low concentrations (500 pM for the full-length GEF-H1 and 3 nM for GEF-H1 1-136 -G4) but strongly avoided GMPCPP-stabilized seeds (Fig. 4b-e).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § Discussion · p. 9

    The structure of the microtubule-GEF-H1-C1 complex revealed a partially compacted lattice and a dimer twist similar to what is seen in GTPγS- and discodermolide-stabilized microtubules.

    “Interestingly, the structure of the microtubule-GEF-H1-C1 complex revealed a partially compacted lattice and a dimer twist similar to what is seen in GTPγS- and discodermolide-stabilized microtubules (Extended Data Fig. 6a,b).”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data
    § Paclitaxel induces the release of GEF-H1 from microtubules in cells · p. 5

    The GFP signal was quantified to ensure comparable expression levels between treatments.

    “quantified the GFP signal to ensure comparable expression levels between treatments (Fig. 3a-e).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data
    § Taxane-induced conformational changes in the microtubule lattice activate GEF-H1-dependent RhoA signalling · p. 1

    Taxanes activate RhoA signalling and induce actin remodelling by releasing the RhoA activator GEF-H1 from microtubules.

    “Here we show that taxanes activate RhoA signalling and induce actin remodelling by releasing the RhoA activator GEF-H1 from microtubules.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § Paclitaxel induces the release of GEF-H1 from microtubules in cells · p. 5

    Experiments were repeated at least three times with similar results.

    “Experiments were repeated at least three times with similar results.”
    • Also stated in: § Paclitaxel induces the release of GEF-H1 from microtubules in cells · p. 5 · plain
      “The experiment was repeated at least three times with similar results.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data
    § Paclitaxel induces the release of GEF-H1 from microtubules in cells · p. 5

    GFP-tagged full-length GEF-H1 was expressed at low and intermediate levels, approximately 2-10 times endogenous levels, in U2OS cells.

    “we expressed green fluorescent protein (GFP)-tagged full-length GEF-H1 (GFP-GEF-H1) at low and intermediate levels (~2-10 times endogenous levels in U2OS cells; Extended Data Fig. 3a,b)”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S1 (asserted), S4 (based).

    Premisereasoning
    § Taxane-induced conformational changes in the microtubule lattice activate GEF-H1-dependent RhoA signalling · p. 2

    Because taxanes stabilize microtubules, they would not be expected to affect GEF-H1 activity.

    “Because taxanes stabilize microtubules, they would not be expected to affect GEF-H1 activity.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § Paclitaxel induces the release of GEF-H1 from microtubules in cells · p. 5

    Paclitaxel-induced cell rounding precluded accurate quantification in live HT1080 cells.

    “however, paclitaxel-induced cell rounding precluded accurate quantification (Supplementary Videos 9 and 10).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data
    § Taxanes activate RhoA through GEF-H1 · p. 2

    Both nocodazole and paclitaxel activate RhoA through GEF-H1.

    “The effects of both nocodazole and paclitaxel, but not the effect of serum on RhoA activity, were largely suppressed in GEF-H1 knockout cells (Fig. 1c,d and Extended Data Fig. 1a-d), indicating that both MTAs activate RhoA through GEF-H1.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data
    § Discussion · p. 7

    Taxanes can rapidly stimulate RhoA signalling by inducing the release of the RhoA activator GEF-H1 from microtubules, thereby triggering actomyosin contractility and cell rounding.

    “In this Article we have demonstrated that taxanes can rapidly stimulate RhoA signalling by inducing the release of the RhoA activator GEF-H1 from microtubules, thereby triggering actomyosin contractility and cell rounding.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § Characterization of GEF-H1-microtubule interactions by in vitro reconstitution assays · p. 7

    The GFP-GEF-H1 preparation had only minor contamination with HSP70 chaperones and 14-3-3 proteins.

    “we used mass spectrometry and detected only minor contamination of the GFP-GEF-H1 preparation with HSP70 chaperones and 14-3-3 proteins (Supplementary Table 1).”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data
    § RhoA2G FRET experiments · p. 14

    The FRET microscope settings had been optimized previously to minimize crosstalk using cells containing only mTFP or mVenus as controls.

    “These settings had been optimized previously to minimize crosstalk using cells containing only mTFP or mVenus as controls.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning
    § Analysis of cell images · p. 17

    Researchers performing the analysis were not blind to the treatment groups associated with the data.

    “Researchers performing the analysis were not blind to the treatment groups associated with the data.”
    • Also stated in: § Life sciences study design · p. 29 · plain
      “Researchers performing the analysis were not blind to the treatment groups associated with the data.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The researchers performing the analysis had no preconceived ideas about the expected results, so lack of blinding did not bias the analysis.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Eukaryotic cell lines · p. 29

    The cell lines used were tested negative for mycoplasma contamination.

    “Cell lines were tested negative for mycoplasma contamination.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Western blotting · p. 13

    Actin was used as a loading control.

    “Actin was used as a loading control.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning
    § Discussion · p. 9

    Taxane treatment overrides native pathways of localized RhoA activation and causes overall RhoA-dependent cell blebbing and rounding, explaining its strong inhibitory effect on cell motility.

    “Taxane treatment overrides these native pathways of localized RhoA activation and causes overall RhoA-dependent cell blebbing and rounding, explaining why it has a strong inhibitory effect on cell motility.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Endogenous GEF-H1 is present at levels sufficient to detect but not to alter microtubule lattice compaction.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning
    § Life sciences study design · p. 29

    All experiments were performed on either cultured cells or purified proteins, so no variability was introduced by the model that would need to be balanced with randomization.

    “All experiments were performed on either cultured cells or purified proteins so there was no variability introduced by our model that would need to be balanced with randomization.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Life sciences study design · p. 28

    Where possible, positive controls were used to test that true differences would be quantifiable.

    “Sample size was limited to practical resource and time constraints, where possible positive controls were used to test that true differences would be quantifiable.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Life sciences study design · p. 28

    Paclitaxel/discodermolide treatment was repeated at least three times.

    “Paclitaxel/Discodermolde treatment was repeated at least 3 times.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Life sciences study design · p. 28

    Sample size was limited to practical resource and time constraints.

    “Sample size was limited to practical resource and time constraints, where possible positive controls were used to test that true differences would be quantifiable.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data
    § Western blotting · p. 13

    The p-MLC signal was first normalized to the actin loading control, and then to the experiment average.

    “Quantifications of p-MLC blots were performed in Image J. The p-MLC signal was first normalized to the actin loading control, and then to the experiment average.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data
    § GEF-H1 knockout cell line generation · p. 13

    GEF-H1 knockout cell lines were screened for GEF-H1 knockout by immunofluorescence, western blotting and targeted sequencing of genomic DNA.

    “These were screened for GEF-H1 knockout (KO) by immunofluorescence, western blotting and by performing targeted sequencing of genomic DNA.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § Analysis of cell images · p. 15

    Protein groups from MaxQuant were filtered to remove reverse hits, contaminants, identifications by site only, and those with only one peptide hit.

    “The iBaq values from the MaxQuant search were imported into Perseus software (v.2.0.11.0), and the protein groups were filtered out for 'Reverse' (false positives), 'Contaminants' and 'Only identified by site', as well as having only one peptide hit, and transferred to excel files for further analysis.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given
    § Life sciences study design · p. 28

    To ensure comparable GFP-GEF-H1 expression levels between treatments, upper and lower thresholds for GFP-GEF-H1 signal were set for each experiment and cells with signal above or below the threshold were excluded.

    “In order to ensure comparable GFP-GEFH1 expression levels between treatments upper and lower thresholds for GFP-GEFH1 signal were set for each experiment and cells with GFP-GEFH1 signal above and below the threshold were excluded.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Study design and conductnone given
    § Cell culture · p. 13

    No commonly misidentified cell lines were used, and cells were not authenticated.

    “No commonly misidentified cell lines were used, and cells were not authenticated.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data
    § Analysis of cell images · p. 17

    Outliers were excluded when most treatments fit a normal distribution and one group would fit a normal distribution with the removal of one or two outliers.

    “For data where most treatments fit a normal distribution and one group would fit a normal distribution with the removal of one or two outliers, these outliers were excluded.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Life sciences study design · p. 28

    For data where most treatments fit a normal distribution and one group would fit a normal distribution with the removal of one or two outliers, those outliers were excluded.

    “For data where most treatments fit a normal distribution and 1 group would fit a normal distribution with the removal of 1 or 2 outliers, these outliers were excluded.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Eukaryotic cell lines · p. 29

    The cell lines used were not authenticated.

    “Cell lines were not authenticated”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § Analysis of cell images · p. 17

    Data on acetylated and non-acetylated GEF-H1 microtubule-to-cytoplasmic ratio were determined not to follow a normal distribution.

    “Data on acetylated and non-acetylated GEF-H1 microtubule-to-cytoplasmic ratio were also determined not to follow a normal distribution.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § Life sciences study design · p. 28

    The sample sizes are justified because significant differences between treatments could be measured with the assays used.

    “Given that we were able to measure significant differences between treatments with our assays we believe the sample sizes have been justified.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data
    § Fig. 4 | Characterization of GEF-H1-microtubule interactions by in vitro · p. 7

    GEF-H1 binding to microtubules is very sensitive to microtubule lattice conformation: it is favoured by compacted, GDP-, GTPγS- or discodermolide-bound lattices, but is incompatible with expanded, GMPCPP- or paclitaxel-bound lattices.

    “Together, these data strongly support the notion that GEF-H1 binding to microtubules is very sensitive to microtubule lattice conformation: it is favoured by compacted, GDP-, GTPγS- or discodermolide-bound lattices, but is incompatible with expanded, GMPCPP- or paclitaxel-bound lattices.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data
    § RhoA G-LISA GTPase activation assay · p. 14

    In the RhoA G-LISA assay, each experiment contained duplicates, background was subtracted, and results were normalized to the experiment mean.

    “Each experiment contained duplicates, the average of the background (lysis buffer only) was subtracted from the average of the sample, and the result was normalized to the mean of the experiment.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning
    § Discussion · p. 9

    The conformational preference of GEF-H1 is optimal for targeting it to cell protrusions where microtubules are actively remodelled, and prevents its sequestration on stable perinuclear microtubules.

    “This conformational preference is optimal for targeting GEF-H1 to cell protrusions where microtubules are actively remodelled, and prevents its sequestration on stable perinuclear microtubules.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Endogenous GEF-H1 is present at levels sufficient to detect but not to alter microtubule lattice compaction.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning
    § Analysis of cell images · p. 17

    Because all experiments were performed on cultured cells or purified proteins, there was no variability introduced by the model that would need to be balanced with randomization.

    “All experiments were performed on either cultured cells or purified proteins, so there was no variability introduced by our model that would need to be balanced with randomization.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning
    § Discussion · p. 9

    GEF-H1 prefers compacted microtubules, a lattice conformation characteristic of dynamic, short-lived microtubules.

    “Instead, GEF-H1 prefers compacted microtubules, a lattice conformation characteristic of dynamic, short-lived microtubules.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Cell culture · p. 13

    Cells were routinely tested for mycoplasma using a commercial assay.

    “Cells were kept at 37 °C with 5% CO2 and routinely tested for mycoplasma using a commercial assay (Mycoaltert assay, LT07-518; Lonza).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Study design and conductnone given
    § Analysis of cell images · p. 15

    The false discovery rate for mass spectrometry analysis was set to 1%.

    “the false discovery rate was set to 1%.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation
    § Characterization of GEF-H1-microtubule interactions by in vitro reconstitution assays · p. 7

    Discodermolide has a notably higher affinity to microtubules than paclitaxel and is a known hypernucleator of microtubules in vitro.

    “Discodermolide has a notably higher affinity to microtubules than paclitaxel and is a known hypernucleator of microtubules in vitro 64,65 .”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [64] Hung, D. T., Chen, J. & Schreiber, S. L. (+)-Discodermolide binds to microtubules in stoichiometric ratio to tubulin dimers, blocks taxol binding and results in mitotic arrest. Chem. Biol. 3, 287–293 https://doi.org/10.1016/s1074-5521(96)90108-8 (1996). source
    • cites [65] ter Haar, E. et al. Discodermolide, a cytotoxic marine agent that stabilizes microtubules more potently than taxol. Biochemistry 35, 243–250 https://doi.org/10.1021/bi9515127 (1996). source

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationreasoning
    § Discussion · p. 9

    Activation of RhoA by taxanes was probably overlooked previously because in cycling cultured cells this effect is quickly overshadowed by mitotic arrest, especially at low concentrations when taxane accumulation is slow.

    “Activation of RhoA by taxanes was probably overlooked previously because, in cycling cultured cells, this effect is quickly overshadowed by mitotic arrest, especially at low concentrations, when taxane accumulation in cells is slow.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductown data
    § Analysis of cell images · p. 15

    For GFP-GEF-H1 binding quantification, cells with comparable GFP-GEF-H1 expression levels across treatment groups were used, with thresholds set to exclude cells outside the range.

    “To ensure comparable GFP-GEF-H1 expression levels between treatments, upper and lower thresholds for the GFP-GEF-H1 signal were set for each experiment, and cells with GFP-GEF-H1 signals above and below the threshold were excluded.”
    • Also stated in: § Analysis of cell images · p. 15 · plain
      “only cells with comparable expression levels across different treatment groups were used for subsequent analysis.”
    Quote in the paperSubstantial claim
75 of 75

  • The paper relies on this without support.

    GEF-H1 knockout cells lack functional GEF-H1.

    “In GEF-H1 knockout cells”

  • The paper relies on this without support.

    U2OS cells are more strongly adherent than HT1080 cells and therefore less prone to rounding up in response to MTA treatment.

    “We chose U2OS cells for these experiments as they are more strongly adherent than HT1080 cells and therefore less prone to rounding up in response to MTA treatment.”

  • The paper relies on this without support.

    GEF-H1 is sensitive to taxanes.

    “To narrow down the origin of GEF-H1's sensitivity for taxanes”

  • The paper relies on this without support.

    Endogenous GEF-H1 is present at levels sufficient to detect but not to alter microtubule lattice compaction.

    “However, endogenous GEF-H1 is a signalling molecule present at levels that are sufficient to detect but not to alter microtubule lattice compaction.”

  • The paper relies on this without support.

    The researchers performing the analysis had no preconceived ideas about the expected results, so lack of blinding did not bias the analysis.

    “However, the researchers involved also had no preconceived ideas as to what the results should look like.”

  • The paper relies on this without support.

    The RhoA2G FRET sensor specifically reports RhoA activity.

    “Lentivirus was used to generate stable cell lines expressing the RhoA2G FRET sensor.”
6 of 6

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • GEF-H1 fragment length differs within Fig. 4 legend

    Minor

    The legend identifies the fragment used in panels m and n as residues 1-136, but identifies the fragment quantified from those wash-in experiments in panel o as residues 1-135.

1 of 1

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Authors
Meiring, J. C. M., Mahapatra, V., Liu, R., Gravett, M. S. C., Morren, D., Saunders, H. A. J., Choi, S. R., Pelster José, A., Karhanova, A., Metallidou, I., Moore, A., Spoelstra, M. F. M., Grigoriev, I. S., Giono, M., Iyer, S. S., Stehbens, S. J., Díaz, J. F., Lansky, Z., Stecker, K. E., Steinmetz, M. O., Howes, S. C., Kapitein, L. C., & Akhmanova, A.
Affiliations
  • The University of Queensland (AU)
  • Utrecht University (NL)
  • Paul Scherrer Institute (CH)
  • Czech Academy of Sciences (CZ)
  • Consejo Superior de Investigaciones Científicas (ES)
  • University of Basel (CH)
Corresponding author
  • Meiring, Joyce C. M.
  • Akhmanova, Anna
ORCID
Venue
Nature Cell Biology
Publisher
Springer Science and Business Media LLC
Published
2026-09-24
ISSN
  • 1465-7392 (ISSN-L)
  • 1476-4679
DOI
10.1038/s41556-026-02079-4
OpenAlex
W7214245033
Semantic Scholar
6cff434afa4d1a756a3e8828dc55d0ffaddb8cb7
Cited by
0
References
101
FWCI
0.00
Type
journal article
Language
en
Open access
Licence
Locations
  • Nature Cell Biology (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DORA PSI (Paul Scherrer Institute) (submittedVersion, cc-by)
  • DIGITAL.CSIC (Spanish National Research Council (CSIC)) (submittedVersion, other-oa)
Funders
  • Broad Institute
  • European Commission (LM2018129)
  • Australian Cancer Research Foundation
  • École Polytechnique Fédérale de Lausanne
  • Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (204125, 320030)
  • Ministerstvo Školství, Mládeže a Tělovýchovy (CZ.02.1.01/ 0.0/0.0/16 013/0001775, LM2018129, CZ.02., CZ.02.1.01, CZ.02.1.01/0.0, 86652036)
  • Nederlandse Organisatie voor Wetenschappelijk Onderzoek (OCENW.XL21.XL21.048, OCENW.XL21, 24.005.009, 184.034.019)
  • China Scholarship Council (184.034.019)
  • Ministerio de Ciencia e Innovación (PID2022-136765OB-I00, PID2022)
  • HORIZON EUROPE Framework Programme
  • National Health and Medical Research Council (2038724)
  • RIKEN
  • European Regional Development Fund (02.1.01/0.0/0.0, CZ.02, CZ.02.1.01, CZ.02.1.01/0.0, /16_013/0001775, LM2018129, CZ.02.1.01/0.0/0.0, CZ.02.1.01/0.0/0.0/16_013/0001775, 86652036)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Microtubule and mitosis dynamics
  • Health Sciences › Medicine › Oncology › Cancer Treatment and Pharmacology
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Protein Kinase Regulation and GTPase Signaling
Keywords
taxanes, GEF-H1, RhoA signaling, microtubule binding, actin cytoskeleton remodeling, GMPCPP, discodermolide, tubulin post-translational modifications

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Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-30.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-30.

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Statistics and arithmetic are recomputed, not judged.

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