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Cited by 0Microtubule and mitosis dynamicsNeuroscience and Neuropharmacology ResearchNeurogenesis and neuroplasticity mechanisms

Active transport by cytoplasmic dynein sustains dendritic MAP2 localization in developing neurons

Open access
Yonemura, Yoji, Sakai, Yuri, Nakata, Rinaho, Hagita-Tatsumoto, Ayaka, Miyasaka, Tomohiro, Misonou, Hiroaki·2026·Journal of Biological Chemistry
DOI 10.1016/j.jbc.2026.113407PMC PMC13571933
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Abstract

MAP2 has been widely used as a marker of neuronal dendrites because of its extensive restriction in the somatodendritic region. Despite that, how the precise localization of such a soluble protein is established and maintained against diffusion has been elusive and long remained a mystery in neuroscience. In this study, using GFP-tagged MAP2 expressed in cultured hippocampal neurons, we discovered a crucial protein region responsible for the localization of MAP2, the serine/proline-rich (S/P) region. Our pulse-chase live-cell imaging revealed the slow but steady migration of MAP2 toward distal dendrites, which was not observed in the presence of a dynein inhibitor. By integrating these experimental parameters into a mathematical model, we demonstrated that an intermittent active transport mechanism by dynein is sufficient to explain the observed MAP2 dynamics. In addition, our experiments using a dynein inhibitor as well as dynein knockdown showed that impaired dynein function leads to mislocalization of MAP2 in the axon. Furthermore, we verified that cytoplasmic dynein binds to MAP2 through the S/P region in heterologous cells. Finally, we show that the failure of this dynein-mediated transport mechanism results in the ectopic stabilization of axonal microtubules, thereby disrupting axonal identity. Thus, we propose that the cytoplasmic dynein recruits and transports free MAP2 toward distal dendrites, thereby maintaining the precise dendritic localization of MAP2. Our findings shed light on the previously unknown mechanism behind MAP2 localization and provide a new direction for soluble protein trafficking research in the field of cell biology of neurons.

AI snapshot

Written from the paper’s full text.

TL;DR

The paper identifies the serine/proline-rich (S/P) region of MAP2 as critical for its somatodendritic localization and shows that cytoplasmic dynein actively transports MAP2 toward distal dendrites. Loss of this dynein-dependent transport causes axonal MAP2 mislocalization and ectopic stabilization of axonal microtubules.

Key findings

  • GFP-MAP2C localized to soma and dendrites despite 3.5 ± 0.5-fold overexpression, with no discernible change in endogenous MAP2; deletion of the S/P region (ΔSP) or N-terminal region (Δ1-308) caused axonal leakage, and restoring S/P to Δ1-308 restored somatodendritic localization.
  • Pulse-chase Dendra2-MAP2C imaging showed biased redistribution toward distal dendrites; ciliobrevin D abolished this bias (ciliobrevin D, p = 0.997, n = 12; DMSO control retained distal bias, p = 0.0014 and p = 0.0039, n = 9).
  • A data-driven model using diffusion of 10 μm²/s, MAP2–MT KD = 4.5 μM, and motor speed 1 μm/s reproduced the slow biased migration; stochastic simulation estimated ~87% MAP2 MT-bound, 8.4% free, and 4.2% transported, with transport dwell time <1 s in 90% of cases and τ = 571 ms.
  • Dynein inhibition or DHC1 knockdown caused axonal MAP2 mislocalization, and ΔSP reduced DHC1 co-immunoprecipitation (geometric mean = 0.45, 95% CI 0.32–0.63, p = 0.0012, n = 7); MAP2C ΔSP also significantly stabilized axonal microtubules.

Methods

  • Cultured embryonic rat hippocampal neurons (E17–18, 3–24 DIV) were transfected at 7 DIV and analyzed by live-cell FRAP and Dendra2 photoconversion, with ciliobrevin D treatment, DHC1 shRNA knockdown, immunofluorescence, co-immunoprecipitation from HEK293 cells and mouse brain lysate, and CRISPR/Cas9 EGFP–β-tubulin knock-in for microtubule FRAP.
  • Transport was modeled in Virtual Cell using reaction–diffusion–advection equations with experimentally or literature-derived parameters, plus particle-based stochastic simulation in Smoldyn.
  • Statistical analysis used GraphPad Prism with normality testing and nonparametric or ANOVA-based tests as appropriate.

Limitations

  • The authors state they could not experimentally demonstrate retrograde MAP2 transport in the axon because axonal Dendra2-MAP2 levels were insufficient for photoconversion; the adaptor linking the S/P region to dynein is unknown; and whether dynein transports free MAP2 directly or as part of a MAP2–microtubule complex remains unresolved.
  • The authors also note that whether inhibiting tubulin acetylation compromises MAP2 localization remains an open question, and that the simulation could not implement fiber representation of microtubules.
  • Evident from the text: the model sets dynein concentration at 5 μM arbitrarily, and ciliobrevin D was used at 50 μM based on prior literature noting that a higher concentration (100 μM) also inhibited kinesin-1 and kinesin-5, leaving some potential for off-target motor effects.

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

Integrity signals

Registry

Crossref · 10.1016/j.jbc.2026.113407

Cites

64 of 64 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

27 of 40 cited sources checked · 17 supported · 2 flagged · accuracy not yet measured

  • Premisecitation

    A recent paper using super-resolution microscopy indicates that there could be even more MTs in dendrites than our estimate.

    “A recent paper using super-resolution microscopy indicates that there could be even more MTs in dendrites than our estimate (23).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [23] Katrukha, 2021, Quantitative mapping of dense microtubule arrays in mammalian neurons, Elife source
  • Premisecitation

    Yu et al. reported that MAP2 staining in dendrites becomes indistinguishable from the axon when dendrites lose minus-end-out MTs.

    “Consistent with this model, Yu et al. reported that MAP2 staining in dendrites becomes indistinguishable from the axon when dendrites lose minus-end-out MTs (33).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [33] Yu, 2000, Depletion of a microtubule-associated motor protein induces the loss of dendritic identity, J. Neurosci. source
  • Findingcitation

    Expressed MAP2 without any native mRNA structures such as a 3′-untranslated region still localizes properly to dendrites.

    “However, we (this paper) and others have shown that expressed MAP2 without any native mRNA structures such as a 3′-untranslated region, which are typically necessary for mRNA transport and local translation (55), still localizes properly to dendrites (11).”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [11] Kaech, 2001, Cytoskeletal microdifferentiation: a mechanism for organizing morphological plasticity in dendrites, Proc. Natl. Acad. Sci. U. S. A. source
    • cites [55] Fernandopulle, 2021, RNA transport and local translation in neurodevelopmental and neurodegenerative disease, Nat. Neurosci. source
  • Findingown data

    Pulse-chase live-cell imaging revealed slow but steady migration of MAP2 toward distal dendrites.

    “Our pulse-chase live-cell imaging revealed the slow but steady migration of MAP2 toward distal dendrites”
    Quote in the paperSubstantial claim
  • Findingown data

    The slow migration of MAP2 toward distal dendrites was not observed in the presence of a dynein inhibitor.

    “which was not observed in the presence of a dynein inhibitor.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. 26
  • May combine two claims. 41

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

    Premisecitation

    MAP2 has been shown to block the path of kinesin motors in in vitro assays.

    “MAP2 has been shown to block the path of kinesin motors in in vitro assays (46, 47, 48, 49, 50).”
    Quote in the paperNot a substantial claim2 of 5 sources checked
    • cites [46] von Massow, 1989, Interaction between kinesin, microtubules, and microtubule-associated protein 2, Cell Motil Cytoskeleton source
    • cites [47] Lopez, 1993, Steric inhibition of cytoplasmic dynein and kinesin motility by MAP2, Cell Motil Cytoskeleton source
    • cites [48] Hagiwara, 1994, Competition between motor molecules (kinesin and cytoplasmic dynein) and fibrous microtubule-associated proteins in binding to microtubules, J. Biol. Chem. source
    • cites [49] Seitz, 2002, Single-molecule investigation of the interference between kinesin, tau and MAP2c, EMBO J. source

      The Discussion says that MAPs, including MAP2c, are obstacles to kinesin attachment, not to its movement along a microtubule. The Abstract likewise reports reduced attachment frequency but no change in speed or run-length once a motor is attached. Thus this in vitro study does not show MAP2 blocking the path of moving kinesin motors. (LLM, conf=0.89)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
    • cites [50] Monroy, 2020, A combinatorial MAP code dictates polarized microtubule transport, Dev. Cell source

  • Classified as probably not a substantial claim.

    Premisecitation

    Previous literature reported that a higher concentration of ciliobrevin D (100 μM) also inhibited kinesin-1 and kinesin-5 motor activity.

    “Concentration of ciliobrevin D, 50 μM, was based on previous literature that reported higher concentration, 100 μM, also inhibited kinesin-1 and kinesin-5 motor activity (18).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [18] Firestone, 2012, Small-molecule inhibitors of the AAA+ ATPase motor cytoplasmic dynein, Nature source

      In the passage discussing Fig. 4d (page unavailable), the paper reports that neither ciliobrevin A nor D significantly affected kinesin-1-dependent microtubule gliding at 100 μM. The passage discussing Fig. 4e likewise says the compounds did not significantly inhibit kinesin-1 or kinesin-5 motor-domain ATPase activity. These findings contradict the attributed claim that 100 μM ciliobrevin D inhibited both motors. (LLM, conf=0.93)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured

  • Classified as probably not a substantial claim.

    Premisecitation

    LMW MAP2C lacking PD still localizes to the soma and dendrites.

    “although LMW MAP2C lacking PD still localizes to the soma and dendrites (11).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [11] Kaech, 2001, Cytoskeletal microdifferentiation: a mechanism for organizing morphological plasticity in dendrites, Proc. Natl. Acad. Sci. U. S. A. source

      The Results (page unavailable) report that MAP2c-GFP is detectable in dendrites and, more weakly, in cell bodies. They do not report localization of MAP2c lacking PD, so the deletion-specific part of the claim is unsupported. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

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

    Premisecitation

    The primary function of MAP2, like Tau, is thought to be binding to MT to stabilize them.

    “The Primary function of MAP2, like Tau, is thought to be binding to MT to stabilize them (3).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [3] Dehmelt, 2005, The MAP2/Tau family of microtubule-associated proteins, Genome Biol. source

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

    Premisecitation

    Loss of the ankyrinG-based AIS has been shown to disrupt the maintenance of neuronal polarity and to allow the axon to acquire molecular features of dendrites, such as axonal MAP2 and postsynaptic proteins.

    “Loss of the ankyrinG-based AIS has been shown to disrupt the maintenance of neuronal polarity and to allow the axon to acquire molecular features of dendrites, such as axonal MAP2 (30) and postsynaptic proteins (31).”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [30] Hedstrom, 2008, AnkyrinG is required for maintenance of the axon initial segment and neuronal polarity, J. Cell Biol. source
    • cites [31] Sobotzik, 2009, AnkyrinG is required to maintain axo-dendritic polarity in vivo, Proc. Natl. Acad. Sci. U. S. A. source

  • Classified as probably not a substantial claim.

    Premisecitation

    Acetylated MTs are oriented uniformly with their minus ends toward the distal end in dendrites.

    “recent studies suggest that acetylated MTs are oriented uniformly with their minus ends toward the distal end in dendrites (15).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [15] Tas, 2017, Differentiation between oppositely oriented microtubules controls polarized neuronal transport, Neuron source

      The Results section, “Minus-End-Out-Oriented Microtubules Are More Stable and More Acetylated” (page not provided), reports that acetylated dendritic microtubules predominantly overlap with minus-end-out microtubules. That supports a preferred orientation toward the distal end, but not the claim that their orientation is uniform. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • Classified as probably not a substantial claim.

    Premisecitation

    MTs in dendrites have mixed orientations.

    “Unlike in the axon, MTs in dendrites have been shown to be mixed in their orientations (14).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [14] Baas, 1988, Polarity orientation of microtubules in hippocampal neurons: uniformity in the axon and nonuniformity in the dendrite, Proc. Natl. Acad. Sci. U. S. A. source

      The matching passage is labeled Abstract, which cannot serve as evidence under the stated rule. Our copy contains no readable full-text passage on dendritic microtubule orientation; the full text appears only as page images, so the claim cannot be verified from admissible text. (LLM, conf=0.75)

      Experimental — accuracy not yet measured

  • Classified as probably not a substantial claim.

    Premisecitation

    MAP2 has been shown to bind to motor proteins in neurons.

    “Since MAP2 has been shown to bind to motor proteins in neurons (13)”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [13] Gumy, 2017, MAP2 defines a pre-axonal filtering Zone to regulate KIF1- versus KIF5-Dependent cargo transport in sensory neurons, Neuron source

      The “MAP2 Interacts with the Coiled-Coil Region of KIF5” section reports that MAP2 co-precipitated with the motor protein KIF5, but that binding experiment used HEK293 cells, not neurons. Experiments in DRG neurons support an interaction between MAP2 and KIF5, but do not directly demonstrate binding in neurons. (LLM, conf=0.84)

      Experimental — accuracy not yet measured

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

    Premisecitation

    Cytoplasmic dynein transports cargo toward the minus end of MT and binds preferably to acetylated MTs like kinesins.

    “Since cytoplasmic dynein transports cargo toward the minus end of MT and binds preferably to acetylated MTs like kinesins (16, 17)”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [16] Reed, 2006, Microtubule acetylation promotes kinesin-1 binding and transport, Curr. Biol. source
    • cites [17] Dompierre, 2007, Histone deacetylase 6 inhibition compensates for the transport deficit in Huntington's disease by increasing tubulin acetylation, J. Neurosci. source

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

    Premisecitation

    The shRNA for rat cytoplasmic DHC1 has been reported to reduce DHC1 in cultured rat Sertoli cells.

    “We used a shRNA for rat cytoplasmic DHC1, which has been reported to reduce it in cultured rat Sertoli cells (29) (Fig. 6C).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [29] Wen, 2018, Dynein 1 supports spermatid transport and spermiation during spermatogenesis in the rat testis, Am. J. Physiol. Endocrinol. Metab. source

      The Materials and Methods say the authors transfected cultured rat Sertoli cells with Dync1h1-specific siRNA duplexes, not shRNA. The Results report that this RNAi reduced Dync1h1 expression by about 70% in those cells. The reduction is supported, but the claim identifies the wrong reagent. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

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

    Premisecitation

    Katrukha et al. reported using super-resolution light microscopy that in dendrites 72 ± 6% of microtubules are acetylated and 26 ± 8% are tyrosinated.

    “Katrukha et al. reported using super-resolution light microscopy that in dendrites 72 ± 6% of microtubules are acetylated and 26 ± 8% are tyrosinated (23).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [23] Katrukha, 2021, Quantitative mapping of dense microtubule arrays in mammalian neurons, Elife source

  • May combine two claims.

    Premisecitation

    We also found that MT-binding of wild-type Tau is quite dynamic like that of MAP2C with faster recovery than the alanine mutant, and that pseudo-phosphorylation mutant with glutamate instead of alanine substitutions exhibited recovery even faster than wild-type Tau.

    “We also found that MT-binding of wild-type Tau is quite dynamic like that of MAP2C with faster recovery than the alanine mutant, and that pseudo-phosphorylation mutant with glutamate instead of alanine substitutions exhibited recovery even faster than wild-type Tau (5).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [5] Iwata, 2019, Regulatory mechanisms for the axonal localization of tau protein in neurons, Mol. Biol. Cell source

      Split into 2 atoms — 0 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 1 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured

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

    Premisecitation

    We have previously shown that most of overexpressed Tau could bind to MTs and therefore exhibited very slow recovery in FRAP, when the phosphorylation sites in the proline-rich region (PRR) of Tau were mutated to alanine to mimic dephosphorylation.

    “We have previously shown that most of overexpressed Tau could bind to MTs and therefore exhibited very slow recovery in FRAP, when the phosphorylation sites in the proline-rich region (PRR) of Tau were mutated to alanine to mimic dephosphorylation (5).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [5] Iwata, 2019, Regulatory mechanisms for the axonal localization of tau protein in neurons, Mol. Biol. Cell source

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

    Premisecitation

    Our recent study suggests that the total number of non-phosphorylated sites in the PRR is more critical for stronger MT-binding of Tau than the status of specific sites in the PRR.

    “Furthermore, our recent study suggests that the total number of non-phosphorylated sites in the PRR is more critical for stronger MT-binding of Tau than the status of specific sites in the PRR (43).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [43] Nakata, 2026, Graded regulation of microtubule-binding of Tau by the phosphorylation state of the proline-rich region in living neurons, Neurosci. Res. source

      The section ‘The Number of Dephospho-mimetic Sites in PRR2 Gradually Modulates Tau-MT Binding’ says that the number of non-phosphorylated residues matters more than the status of a few critical sites. The study tested dephospho-mimetic sites in PRR2, however, so it does not establish the claim for the broader proline-rich region (PRR). (LLM, conf=0.82)

      Experimental — accuracy not yet measured

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

    Premisecitation

    Tas et al. also showed that acetylated and tyrosinated MTs are separated, and that acetylated MT fraction contains more minus-end-out MTs than tyrosinated MTs (66% vs 34%).

    “They also showed that acetylated and tyrosinated MTs are separated, and that acetylated MT fraction contains more minus-end-out MTs than tyrosinated MTs (66% vs 34%).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [15] Tas, 2017, Differentiation between oppositely oriented microtubules controls polarized neuronal transport, Neuron source

      The Results section reports that acetylated and tyrosinated microtubules form spatially separated subsets, and that acetylated microtubules predominantly overlap with minus-end-out microtubules. But the 66% versus 34% figures describe microtubule orientations in a stable network remaining after nocodazole treatment, not a comparison of the acetylated and tyrosinated fractions. The passage also inconsistently assigns those figures to plus- and minus-end-out microtubules, respectively, despite saying minus-end-out microtubules were more abundant. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

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

    Premisecitation

    Tas et al. reported that plus-end-out and minus-end-out MTs are bundled and separated in dendrites, promoting persistent moving in a certain direction because of reduced potential switching to oppositely oriented MTs.

    “Tas et al. reported that plus-end-out and minus-end-out MTs are bundled and separated in dendrites, promoting persistent moving in a certain direction because of reduced potential switching to oppositely oriented MTs (15).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [15] Tas, 2017, Differentiation between oppositely oriented microtubules controls polarized neuronal transport, Neuron source

  • May combine two claims.

    Findingown data

    Some posttranslational modifications such as acetylation differ between the axon and dendrites in very immature neurons, but they are more uniformly present in these two compartments after 7 DIV.

    “Although some posttranslational modifications such as acetylation differ between the axon and dendrites in very immature neurons (54), they are more uniformly present in these two compartments after 7 DIV (unpublished observations), which we used in the study.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [54] Hammond, 2010, Posttranslational modifications of tubulin and the polarized transport of kinesin-1 in neurons, Mol. Biol. Cell source

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

    Premisecitation

    Dynein is reported to transport cargoes both anterogradely and retrogradely in dendrites where orientation of MTs is considered to be mixed.

    “Dynein, which moves toward minus-end of MTs, is reported to transport cargoes both anterogradely (38, 39) and retrogradely (40, 41) in dendrites where orientation of MTs is considered to be mixed.”
    Quote in the paperSubstantial claim2 of 4 sources checked
    • cites [38] Kapitein, 2010, Mixed microtubules steer dynein-driven cargo transport into dendrites, Curr. Biol. source
    • cites [39] van Spronsen, 2013, TRAK/Milton motor-adaptor proteins steer mitochondrial trafficking to axons and dendrites, Neuron source
    • cites [40] Ayloo, 2017, Dynein efficiently navigates the dendritic cytoskeleton to drive the retrograde trafficking of BDNF/TrkB signaling endosomes, Mol. Biol. Cell source
    • cites [41] Yap, 2022, Dynein is required for Rab7-Dependent endosome maturation, retrograde dendritic transport, and degradation, J. Neurosci. source

  • May combine two claims.

    Interpretationreasoning

    In dendrites, it seems that ∼50% of microtubules are oriented with minus-end out (72% × 66% = ∼48%), consistent with the finding that ∼50% of microtubules are oriented with minus-end out throughout the dendrite.

    “Therefore, in dendrites, it seems that ∼50% of microtubules are oriented with minus-end out (72% × 66% = ∼48%), which is consistent with the finding that ∼50% of microtubules are oriented with minus-end out throughout the dendrite (15).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [15] Tas, 2017, Differentiation between oppositely oriented microtubules controls polarized neuronal transport, Neuron source

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

    Study design and conductcitation

    A power analysis was performed using G*Power with parameters taken from previous reports or similar experiments.

    “Power analysis was performed using G∗Power (59, 60) with parameters taken from previous reports or similar experiments.”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [59] Faul, 2007, G∗Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences, Behav. Res. Methods source
    • cites [60] Faul, 2009, Statistical power analyses using G∗Power 3.1: tests for correlation and regression analyses, Behav. Res. Methods source

  • May combine two claims.

    Findingown data

    Failure of dynein-mediated transport results in ectopic stabilization of axonal microtubules, thereby disrupting axonal identity.

    “Finally, we show that the failure of this dynein-mediated transport mechanism results in the ectopic stabilization of axonal microtubules, thereby disrupting axonal identity.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Overexpression of GFP-MAP2C did not result in any discernable difference in endogenous MAP2 expression or localization.

    “It should also be noted that overexpression of GFP-MAP2C did not result in any discernable difference in endogenous MAP2 expression or localization (Fig. 1C).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The AIS remained intact in ΔSP-expressing neurons, with AnkG signal intensity comparable to that of WT-expressing or untransfected neighboring neurons.

    “The AIS remained intact in ΔSP-expressing neurons, with AnkG signal intensity comparable to that of WT-expressing (Fig. S6A) or untransfected neighboring neurons in the same imaging field (Fig. S6B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Ciliobrevin D disrupted anterograde transport of MAP2C in dendrites, such that there was no obvious biased redistribution of converted MAP2C.

    “Intriguingly, the inhibitor disrupted the anterograde transport of MAP2C in dendrites (Fig. 3D), such that there was no obvious biased redistribution of converted MAP2C (Fig. 3E).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    MAP2C and DHC1 co-immunoprecipitate and bind in vitro.

    “This resulted in the co-immunoprecipitation of MAP2C and DHC1 and demonstrated their binding in vitro (Fig. 7B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    MAP2 MT-binding in both dendrites and axon is dynamic and a fraction of MAP2C is in the diffusible state at all times.

    “Interestingly, the recovery in the second timescale indicated that MAP2 MT-binding in both dendrites and the axon is dynamic and that a fraction of MAP2C is in the diffusible state at all times (Fig. 2A).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    MT depolymerization by nocodazole accelerated fluorescence recovery of MAP2C compared to untreated control, confirming dynamic behavior is MT-dependent and MAP2C enters almost freely diffusible state upon MT depolymerization.

    “MT depolymerization by nocodazole further accelerated the fluorescence recovery of MAP2C (Fig. S2) compared to the untreated control, confirming that the dynamic behavior of MAP2C is MT-dependent and that MAP2C enters an almost freely diffusible state upon MT depolymerization.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Endogenous MAP2 concentration in adult mouse cortices is 1.85 nmol/g wet tissue, about 5.6 μM assuming somata and dendrites occupy one-third of total volume.

    “Our measurement indicated 1.85 nmol/g wet tissue, which gave about 5.6 μM with an assumption that somata and dendrites occupy one-third of the total volume.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Somata and dendrites occupy one-third of the total volume.

  • May combine two claims.

    Findingown data

    Best-fit diffusion coefficients from FRAP simulation were 22.5 μm2/s for GFP and 12.5 μm2/s for ΔMTBD.

    “We estimated best-fit values by plotting the reciprocals of the sum of squares between the data and simulation results and found 22.5 μm2/s for GFP and 12.5 μm2/s for ΔMTBD as respective best-fit values (Fig. 4C).”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: The FRAP procedure results in full conversion of GFP to a permanently dark state, such that recovery solely reflects molecular motions.

  • May combine two claims.

    Findingown data

    With the kon and koff used, MT-binding was transient with median dwell time 140 ms and τ 239 ms, comparable to the predicted residence time 222 ms.

    “With the kon and koff that we used, MT-binding was transient with median and τ of dwell time at 140 and 239 ms, respectively, which is comparable to the predicted residence time (1/koff), 222 ms.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In most cases, signal was redistributed more to the distal direction than the proximal direction of the dendrite, indicating slow dendritic transport of MAP2C toward distal dendrites.

    “In most cases, the signal was redistributed more to the distal direction than the proximal direction of the dendrite (Fig. 2G), indicating slow dendritic transport of MAP2C toward distal dendrites.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Virtual kymograph of converted MAP2 showed gradual spreading due to diffusion and drifting of center due to transport, similar to imaging experiments.

    “Virtual kymograph of the converted species (red MAP2) showed a gradual spreading of the species due to diffusion and drifting of the center of distribution because of the transport (Fig. 4E upper panel). This was similar to the kymograph from imaging experiments.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The stochastic simulation estimated that about 87% of MAP2 is bound to MTs, 8.4% free, and 4.2% being transported at a given point in time.

    “The model estimated that about 87% of MAP2 is bound to MTs, 8.4% free, and 4.2% being transported (bound to motor and MT) at a given point in time.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    MAP2C natively lacking PD still exhibited somatodendritic localization, indicating that PD is not necessary for the somatodendritic localization of MAP2.

    “However, we showed that MAP2C natively lacking PD still exhibited somatodendritic localization, indicating that PD is not necessary for the somatodendritic localization of MAP2.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The transport of MAP2 observed was biased toward dendrites, with an apparent velocity of ∼0.03 μm/s.

    “The transport of MAP2 we observed was biased toward dendrites, with an apparent velocity of ∼0.03 μm/s, which is within the reported velocity range of the dendritic transport of RNA (0.005–0.1 μm/s) (34, 35, 36).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The S/P region is essential for MAP2 transport, as its deletion abolishes transport despite the intact microtubule-binding domain.

    “Our data show that the S/P region is essential for this process, as its deletion abolishes transport despite the intact microtubule-binding domain.”
    Quote in the paperSubstantial claim

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

    Findingown data

    In the simulation, kon values larger than 1 μM−1s−1 provided koff values with a similar fit to those obtained at 1 μM−1s−1.

    “kon larger than 1 μM−1s−1 provided koff with similar fit to the values obtained at 1 μM−1s−1.”
    Quote in the paperNot a substantial claim

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

    Findingown data

    The minimum kon that provided a fit as good as 1 μM−1s−1 or higher was around 0.1 μM−1s−1.

    “The minimum kon, which provided a fit as good as with 1 μM−1s−1 or higher, was around 0.1 μM−1s−1.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Kanai et al. reported that the projection domain (PD) of MAP2 prevents MAP2 from entering the axon, resulting in somatodendritic localization of HMW MAP2.

    “Kanai et al. (6) also reported that the projection domain (PD) of MAP2, which exists only in MAP2A and B, prevents MAP2 from entering the axon, resulting in the somatodendritic localization of HMW MAP2”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [6] Kanai, 1995, Sorting mechanisms of tau and MAP2 in neurons: suppressed axonal transit of MAP2 and locally regulated microtubule binding, Neuron source

  • Classified as probably not a substantial claim.

    Premisecitation

    MAP2 localizes predominantly to the cell body and dendrites.

    “MAP2 is one of microtubule (MT) associated proteins (MAPs) and has been known to localize predominantly to the cell body and dendrites (1, 2).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [1] Bernhardt, 1984, Light and electron microscopic studies of the distribution of microtubule-associated protein 2 in rat brain: a difference between dendritic and axonal cytoskeletons, J. Comp. Neurol. source
    • cites [2] De Camilli, 1984, Distribution of microtubule-associated protein 2 in the nervous system of the rat studied by immunofluorescence, Neuroscience source

  • May combine two claims.

    Interpretationown data

    A fraction of polymerizing MTs (10% moving at 0.1 μm/s) did not exhibit the drift speed observed experimentally, confirming motor-dependent mechanism is more appropriate.

    “This did not exhibit the drift speed we observed experimentally, confirming that the motor-dependent mechanism is more appropriate.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Dynein actively maintains MAP2 within the somatodendritic compartment, and impairment of this mechanism leads to mislocalization of MAP2 to the axon.

    “Our findings suggest that dynein actively maintains MAP2 within the somatodendritic compartment, and that impairment of this mechanism leads to the mislocalization of MAP2 to the axon.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Both dendritic transport and the somatodendritic localization depend on the S/P domain of MAP2 and dynein.

    “Taken together, these results suggest that both dendritic transport and the somatodendritic localization depend on the S/P domain of MAP2 and dynein.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    The S/P region is critical for DHC1 binding, MAP2 transport, and localization of MAP2.

    “These results suggest that the S/P region is critical for DHC1 binding, MAP2 transport, and localization of MAP2, thereby supporting our hypothesis.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    Neurons treated with ciliobrevin D were alive and exhibited normal morphology.

    “It should be noted that neurons were alive and exhibited normal morphology after the treatment (Fig. S4, A and B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    The transport model, built on experimental parameters, successfully captures the slow and biased migration of MAP2C observed in neurons, supporting that an intermittent active transport mechanism can account for its dendritic dynamics.

    “These results therefore demonstrate that our transport model, built on experimental parameters, successfully captures the slow and biased migration of MAP2C observed in neurons, supporting the idea that an intermittent active transport mechanism can account for its dendritic dynamics.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    MAP2 binds to MTs quite stably in in vitro binding assays.

    “This was surprising because MAP2 binds to MTs quite stably in in vitro binding assays (42).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [42] Itoh, 1997, Phosphorylation states of microtubule-associated protein 2 (MAP2) determine the regulatory role of MAP2 in microtubule dynamics, Biochemistry source

  • May combine two claims.

    Interpretationreasoning

    The balance between stability and mobility is likely essential for the active maintenance of MAP2's somatodendritic distribution, as demonstrated by the mislocalization of the ΔSP mutant.

    “This balance between stability and mobility is likely essential for the active maintenance of its somatodendritic distribution, as demonstrated by the mislocalization of the ΔSP mutant.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    The AIS remained intact in ΔSP-expressing neurons despite clear axonal MAP2 mislocalization, arguing against the possibility that disruption of the AIS-based barrier underlies the observed mislocalization.

    “Furthermore, the AIS remained intact in ΔSP-expressing neurons despite clear axonal MAP2 mislocalization (Fig. S6B), arguing against the possibility that disruption of the AIS-based barrier underlies the observed mislocalization.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    Kapitein et al. demonstrated using quantitative modeling that dynein can transport cargo into dendrites where orientation of microtubules is 50% minus-end out, without considering findings that MTs are bundled and separated.

    “Furthermore, Kapitein et al. demonstrated using quantitative modeling that dynein can transport cargo into dendrites where orientation of microtubules is 50% minus-end out, without considering findings that MTs are bundled and separated (38).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [38] Kapitein, 2010, Mixed microtubules steer dynein-driven cargo transport into dendrites, Curr. Biol. source

  • May combine two claims.

    Interpretationreasoning

    Wild-type Tau is phosphorylated at certain residues in the proline-rich region and thus exhibits dynamic MT-binding in neurons.

    “These results indicated that wild-type Tau is phosphorylated at certain residues in the proline-rich region and thus exhibits dynamic MT-binding in neurons.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    In both models, the S/P region is central to dynein-mediated transport, distinguishing this mechanism from passive piggybacking that would be independent of the S/P region.

    “In both models, the S/P region is central to dynein-mediated transport, distinguishing this mechanism from passive piggybacking that would be independent of the S/P region.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Transport and localization of MAP2 are inhibited by S/P deletion and dynein inhibitor or knockdown.

    “Our experimental results showed that transport and localization of MAP2 are inhibited by S/P deletion and dynein inhibitor or knockdown.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    FRAP data and stochastic simulation suggest that MT-binding of MAP2 in living neurons is quite dynamic, with an estimated KD of 1-3 μM (depending on the estimated level of MTs).

    “Our FRAP data and stochastic simulation suggest that MT-binding of MAP2 in living neurons is quite dynamic, with an estimated KD of 1–3 μM (depending on the estimated level of MTs).”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: FRAP recovery kinetics reflect microtubule-binding dynamics of MAP2 in living neurons.

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

    Study design and conductnone given

    Data were tested for normality and lognormality using D'Agostino-Pearson, Anderson-Darling, Shapiro-Wilk, and Kolmogorov-Smirnov tests.

    “Data were tested for normality and lognormality using D'Agostino–Pearson, Anderson–Darling, Shapiro–Wilk, and Kolmogorov–Smirnov tests.”
    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 conductnone given

    Data that did not follow a normal distribution were analyzed using nonparametric tests (two-tailed Mann-Whitney U test for two-group comparisons; one-sample Wilcoxon signed-rank test for ratio data), and lognormally distributed ratio data were analyzed with a one-sample ratio t test.

    “Data that did not follow a normal distribution were analyzed using nonparametric tests (two-tailed Mann–Whitney U test for two-group comparisons; one-sample Wilcoxon signed-rank test for ratio data); lognormally distributed ratio data were analyzed with a one-sample ratio t test.”
    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 conductnone given

    The other antibodies used were well-characterized and produced staining patterns consistent with their previously reported localizations.

    “Other antibodies are well-characterized and showed staining patterns consistent with their previously reported localizations.”
    Quote in the paperNot a substantial claim
57 of 57

  • The authors state this as an assumption.

    The FRAP procedure results in full conversion of GFP to a permanently dark state, such that recovery solely reflects molecular motions.

    “These estimates were made based on the assumption that the FRAP procedure results in the full conversion of GFP to a permanently dark state, such that the recovery solely reflects molecular motions.”

  • The authors state this as an assumption.

    The 5% recovery observed after fixing cells reflects a fraction of GFP in the reversible dark state.

    “We performed FRAP after fixing the cells and observed 5% recovery within 5 s, which we assumed to reflect a fraction of GFP in the reversible dark state.”

  • The authors state this as an assumption.

    Somata and dendrites occupy one-third of the total volume.

    “with an assumption that somata and dendrites occupy one-third of the total volume.”

  • The authors state this as an assumption.

    2–3 tubulin heterodimers provide a MAP2-binding site with three MT-binding repeats.

    “Assuming that 2–3 tubulin heterodimers provide a MAP2-binding site with three MT-binding repeats (24)”

  • The paper relies on this without support.

    How the specific somatodendritic localization of MAP2 is established and maintained is largely unknown.

    “Despite the utility and significance of the somatodendritic localization of MAP2, still very little is known about how the specific localization is established and maintained.”

  • The paper relies on this without support.

    Ciliobrevin D specifically inhibits cytoplasmic dynein in these neurons without other effects that could cause MAP2 mislocalization.

    “neurons at 14 DIV were treated with 50 μM ciliobrevin D for either 24 h or 48 h and analyzed for endogenous MAP2 localization.”
    “Dynein knockdown did result in leakage of MAP2 into the axon similar to that observed with the pharmacological inhibition (Figs. 6, D, E and S5C).”

  • The paper relies on this without support.

    The shRNA against rat DHC1 specifically reduces dynein without off-target effects that could cause MAP2 mislocalization.

    “We used a shRNA for rat cytoplasmic DHC1, which has been reported to reduce it in cultured rat Sertoli cells (29) (Fig. 6C).”
    “GFP-positive shRNA-transfected neurons showed significantly reduced DHC1 signal compared to untransfected neurons.”

  • The paper relies on this without support.

    FRAP recovery kinetics reflect microtubule-binding dynamics of MAP2 in living neurons.

    “Our FRAP data and stochastic simulation suggest that MT-binding of MAP2 in living neurons is quite dynamic, with an estimated KD of 1–3 μM (depending on the estimated level of MTs).”

  • The paper relies on this without support.

    At 50 μM, ciliobrevin D selectively inhibits cytoplasmic dynein without inhibiting kinesin-1 or kinesin-5.

    “Concentration of ciliobrevin D, 50 μM, was based on previous literature that reported higher concentration, 100 μM, also inhibited kinesin-1 and kinesin-5 motor activity (18).”
9 of 9

Statistics recomputed

Every reported test result, recomputed from its test statistic and degrees of freedom. A result shows as not adding up only once an independent check has confirmed it.

  • ConsistentF(3, 41) = 6.58reported p = .001 · recomputed p < .001

    “F(3, 41) = 6.58, p = .0010”

  • ConsistentF(1, 41) = 19.29reported p < .0001 · recomputed p < .001

    “F(1, 41) = 19.29, p < .0001”

  • ConsistentF(3, 41) = 1.4reported p = .26 · recomputed p = .256

    “F(3, 41) = 1.40, p = .26”

  • ConsistentF(1.928, 607.3) = 45.73reported p < .0001 · recomputed p < .001

    “F(1.928, 607.3) = 45.73, p < .0001”

  • ConsistentF(17.35, 607.3) = 0.7367reported p = .7688 · recomputed p = .769

    “F(17.35, 607.3) = 0.7367, p = .7688”

5 of 5

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.

  • Dynein-inhibitor FRAP difference is described as both significant and nonsignificant

    Major

    The results call the decrease in MAP2C fluorescence recovery significant, while the caption for the same FRAP comparison says the two datasets could be fitted with a single curve with no statistical differences.

  • Discussion KD range excludes the reported fit

    Minor

    The discussion summarizes the estimated MAP2-microtubule KD as 1-3 μM, but the results report a fitted value of 4.5 μM.

  • Discussion cites a photoconversion panel for an axon-dendrite FRAP comparison

    Minor

    The discussion points to Figure 2B for FRAP recovery in axons and dendrites, but the caption identifies Figure 2B as dendritic photoconversion; Figure 2A is the axon-and-dendrite FRAP panel.

3 of 3

Cites

Flagged first, then by citations

Authors
Yonemura, Y., Sakai, Y., Nakata, R., Hagita-Tatsumoto, A., Miyasaka, T., & Misonou, H.
Affiliations
Doshisha University (JP)
ORCID
Venue
Journal of Biological Chemistry
Publisher
Elsevier BV
Published
2026-10
Volume
302
Issue
10
Pages
113407
ISSN
0021-9258 (ISSN-L)
DOI
10.1016/j.jbc.2026.113407
PMC
PMC13571933
OpenAlex
W7201874493
Semantic Scholar
545be63591269121440d080a00673cec4cb8506d
Cited by
0
References
63
FWCI
0.00
Type
journal article
Language
en
Open access
Licence
Locations
  • Journal of Biological Chemistry (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • PubMed Central (submittedVersion, cc-by)
Funders
  • Promotion and Mutual Aid Corporation for Private Schools of Japan
  • University Fellowship Creation Project for Creating Scientific and Technological Innovation (JPMJFS2145)
  • Japan Science and Technology Agency (JPMJSP2129)
  • Government of Japan Ministry of Education Culture Sports Science and Technology
  • Japan Society for the Promotion of Science (22H02946, 25K18498, 23KJ2078)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Microtubule and mitosis dynamics
  • Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neuroscience and Neuropharmacology Research
  • Life Sciences › Neuroscience › Developmental Neuroscience › Neurogenesis and neuroplasticity mechanisms
Keywords
cytoplasmic dynein, MAP2, dendritic localization, active transport, dendrite formation, hippocampal neurons

About these checks

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 2026-10-24.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-24.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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