Tau hyperphosphorylation impairs cooperative binding to microtubules and perturbs organelle trafficking in neurons

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

Tau contains ~85 predicted phosphorylation sites.

“Tau contains ~85 predicted phosphorylation sites (Hanger et al., 2009; Chakraborty et al., 2024).”

• cites Hanger et al., 2009 sourceNot checked — no full text of the source
• cites Chakraborty et al., 2024 sourceSupported

Classified as probably not a substantial claim.

Cooperativity leads to cohesive envelope-like structures.

“Cooperativity leads to cohesive envelope-like structures (Dixit et al., 2008; Hinrichs et al., 2012; McVicker et al., 2014; Siahaan et al., 2019; Tan et al., 2019; Siahaan et al., 2022).”

• cites Dixit et al., 2008 sourceNot checked — no full text of the source
• cites Hinrichs et al., 2012 sourceCould not verify

  The Results and “Tau Diffusion along Microtubules” sections describe Tau binding and diffusion, including mobile and immobile populations. Searches for cooperativity, cohesive envelope-like structures, and Tau patches found no passage linking cooperative binding to formation of those structures. (LLM, conf=0.75)

  Experimental — accuracy not yet measured
• cites McVicker et al., 2014 sourcePartly supported

  The Results report that tau forms multi-molecule complexes on paclitaxel-stabilized microtubules, and the Discussion describes patches of tau. These findings support the idea of cohesive groupings, but the paper does not show that cooperativity causes them or describe them as envelope-like structures; on GMPCPP-stabilized microtubules, tau instead binds as single molecules. The supplied copy gives no page numbers for these passages. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

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

Tau's function and microtubule affinity are modulated by alternative splicing and phosphorylation.

“Tau’s function and microtubule affinity are modulated by alternative splicing (Kellogg et al., 2018; McVicker et al., 2014) and phosphorylation, both of which play key roles in normal development and pathology”

• cites Kellogg et al., 2018 sourceSupported
• cites McVicker et al., 2014 sourceSupported
• cites Lindwall and Cole, 1984 sourceNot checked — no full text of the source

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

Tau expressed in HEK cells is phosphorylated by endogenous kinases at 58 residues, with <15% occupancy, indicating substantial heterogeneity among tau molecules.

“For example, tau expressed in HEK cells is phosphorylated by endogenous kinases at 58 residues, with <15% occupancy, indicating substantial heterogeneity among tau molecules (Fan et al., 2025).”

• cites Fan et al., 2025 sourcePartly supported

  The Characterization section (p. 4) reports 52 phosphorylated sites in HEK tau, not 58; 58 is the count for Sf9 tau. The same section attributes phosphorylation in these cells to endogenous kinases. On p. 5, the paper says occupancy is below approximately 15% at most sites, not all sites, which is consistent with variation among tau molecules. (LLM, conf=0.92)

  Experimental — accuracy not yet measured

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

Discontinuous patterning of tau along microtubules, consistent with envelopes, was observed in live non-neuronal U-2 OS cells following taxol treatment or elevated pH, and by immunofluorescence in fixed hippocampal neurons.

“Discontinuous patterning of tau along microtubules, consistent with envelopes, was also observed in live, non-neuronal U-2 OS cells following taxol treatment (Siahaan et al., 2022) or with elevated pH (Siahaan et al., 2026), and by immunofluorescence staining in fixed hippocampal neurons (Tan et al., 2019).”

• cites Siahaan et al., 2022 sourceSupported
• cites Siahaan et al., 2026 sourcePartly supported

  The Results section (‘Tau phosphorylation affects envelope formation in cells’; page unavailable) reports that elevated pH revealed separated tau patches along microtubules, consistent with tau envelopes. But the Methods section (‘Live-cell experiments’; page unavailable) identifies the cells used for elevated-pH live imaging as IMCD-3, not U-2 OS. The taxol and hippocampal-neuron observations are attached to other citations in the citing sentence. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites Tan et al., 2019 sourceSupported

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

Tau does not form envelopes on GMPCPP-polymerized microtubules, but readily forms envelopes on compacted GDP-lattices or reversibly expanded taxol-lattices.

“Tau does not form envelopes on GMPCPP-polymerized microtubules, which are irreversibly expanded, mimicking the GTP-state, but readily forms envelopes on compacted GDP-lattices or reversibly expanded taxol-lattices”

• cites Dixit et al., 2008 sourceNot checked — no full text of the source
• cites Monroy et al., 2018 sourceCould not verify

  The Results section (‘MAP7 and tau exhibit overlapping localization patterns’; page unavailable) reports tau binding to taxol-stabilized microtubules, but does not establish envelope formation. Searches for ‘envelopes,’ ‘GMPCPP,’ and compacted GDP lattices found no passage comparing envelope formation across those lattice states. (LLM, conf=0.76)

  Experimental — accuracy not yet measured
• cites Tan et al., 2019 sourcePartly supported

  The paper’s passage labeled Abstract (page unavailable) reports that tau condensates formed on taxol-stabilized and native GDP microtubule lattices, but not on GMP-CPP lattices. It also reports that GMP-CPP lattices are expanded relative to GDP lattices. Our copy does not establish the sentence’s further descriptions of GMP-CPP expansion as irreversible or taxol-lattice expansion as reversible. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

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

Some motors, such as kinesin-1 and kinesin-3, are strongly inhibited by tau in an isoform- and lattice-dependent manner, while kinesin-2 and dynein can more effectively navigate tau-decorated regions.

“While some motors, such as kinesin-1 and kinesin-3, are strongly inhibited by tau in an isoform- and lattice-dependent manner, others, like kinesin-2 and dynein, can more effectively navigate tau-decorated regions”

• cites Dixit et al., 2008 sourceNot checked — no full text of the source
• cites Vershinin et al., 2007 sourcePartly supported

  The Results and Discussion (page unavailable) show that tau inhibits transport by multiple kinesin-I motors, with a much stronger effect from 3RS than 4RL tau. The Materials and Methods (page unavailable) identify kinesin-I as the motor studied and say the preparation contained no dynein. The paper does not establish the claimed effects on kinesin-3 or kinesin-2, their relative ability to navigate tau-decorated regions, or dependence on lattice type. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites McVicker et al., 2011 sourcePartly supported

  The Results report that tau shortened the runs of the kinesin motor studied, with 3RS-tau more inhibitory than 4RL-tau; the Discussion says inhibition also depends on the microtubule lattice state. Experimental Procedures identify that motor as KIF5C, a kinesin-1 motor. The paper does not establish the claimed effects on kinesin-3 or that kinesin-2 and dynein navigate tau-decorated regions more effectively. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

May combine two claims.

Tau binds to microtubules in two distinct kinetic phases: cooperative binding that results in the formation of cohesive envelopes and diffusive binding along microtubules.

“Our initial observations, consistent with previous studies, showed that tau binds to microtubules in two distinct kinetic phases: cooperative binding that results in the formation of cohesive envelopes and diffusive binding along microtubules”

• cites Hinrichs et al., 2012 sourcePartly supported

  The paper reports Tau diffusion along microtubules and describes mobile and immobile populations (Tau Diffusion along Microtubules; page not provided). It does not establish two kinetic phases of binding or say that cooperative binding forms cohesive envelopes. An immobile population is not evidence for that proposed phase. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites McVicker et al., 2014 sourcePartly supported

  The Discussion (page unavailable) reports that tau transitions between diffusing and static states and can form complexes of 2–3 molecules on the microtubule lattice. It does not characterize these as two kinetic phases or establish that cooperative binding produces cohesive envelopes; the Results also show that complex formation depends on how the microtubules are stabilized. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites Stern et al., 2017 sourcePartly supported

  The Results (Figure 3; page unavailable) show that Tau can bind statically or move dynamically along the microtubule surface, and the Discussion describes concentration-dependent multiprotein patches. The paper does not describe these as two kinetic phases in which cooperative binding produces cohesive envelopes; it also says static binding at low concentration is not governed by complex formation. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

May combine two claims.

Tau exhibits both diffusive and cooperative interactions with microtubules.

“Tau exhibits both diffusive and cooperative interactions with microtubules.”

• cites Dixit et al., 2008 sourceNot checked — no full text of the source
• cites Hinrichs et al., 2012 sourcePartly supported

  The paper reports that approximately half of the observed Tau molecules diffused along microtubules (opening summary, page unavailable). It does not establish cooperative interactions: the discussion says the changes expected from Tau clustering as concentration increased were not observed. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites McVicker et al., 2014 sourcePartly supported

  The Results report diffusing Tau and show that Tau forms multi-molecule complexes on paclitaxel-stabilized microtubules. They do not establish that Tau binds cooperatively; the Discussion uses “cooperative” to describe doublecortin, not Tau. Thus the diffusive interaction is supported, but the cooperative interaction is not established by this paper. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

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

Axonal microtubules are considered to be highly stable.

“While axonal microtubules are considered to be highly stable (Black et al., 1984; Brady et al., 1984; Sahenk and Brady, 1987; Lim et al., 1989; Okabe and Hirokawa, 1990; Baas et al., 1991; Ahmad et al., 1993; Li and Black, 1996; Song et al., 2013)”

• cites Black et al., 1984 sourceNot checked — no full text of the source
• cites Brady et al., 1984 sourceSupported
• cites Sahenk and Brady, 1987 sourceNot checked — no full text of the source

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

Envelope formation is sensitive to the intramolecular lattice spacing between α and β tubulin.

“Envelope formation is sensitive to the intramolecular lattice spacing between α and β tubulin.”

• cites Dixit et al., 2008 sourceNot checked — no full text of the source
• cites Monroy et al., 2018 sourceCould not verify

  The Results section discusses MAP7 and tau competing for binding on the microtubule lattice, but does not address envelope formation or spacing between α- and β-tubulin. Searches for those terms and their paraphrases found no passage supporting the claim; page numbers were not available in our copy. (LLM, conf=0.76)

  Experimental — accuracy not yet measured
• cites Tan et al., 2019 sourcePartly supported

  The passage labelled Abstract (page not given) reports that tau condensates form on some microtubule lattices but not others, and hypothesizes that spacing affects condensation. It specifies spacing between tubulin dimers, not spacing between α- and β-tubulin within a dimer; it also presents the spacing mechanism as a hypothesis rather than an established result. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Lysosomes are transported by teams of kinesin-1, -2, and -3 and dynein motors.

“lysosomes are transported by teams of kinesin-1, -2, and -3 and dynein motors”

• cites Jordens et al., 2001 sourceNot checked — no full text of the source
• cites Brown et al., 2005 sourceNot checked — no full text of the source
• cites Loubéry et al., 2008 sourcePartly supported

  The section “Kinesin-2 but not kinesin-1 moves late endosomes and lysosomes” reports that kinesin-2 moves these compartments, but says kinesin-1 and dynein do not appear to move them directly. The paper does not identify kinesin-3 as a lysosome motor or show that the listed motors transport lysosomes as teams; its discussion of multiple motors working together concerns peroxisomes. Page numbers are unavailable in our copy. (LLM, conf=0.90)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Previous studies showed that tau differentially regulates motor proteins, with kinesin-1 and kinesin-3 being more sensitive to tau-mediated inhibition than kinesin-2 and dynein.

“Previous studies showed that tau differentially regulates motor proteins, with kinesin-1 and kinesin-3 being more sensitive to tau-mediated inhibition than kinesin-2 and dynein”

• cites Dixit et al., 2008 sourceNot checked — no full text of the source
• cites Vershinin et al., 2007 sourcePartly supported

  The Results and Discussion report that tau reduces kinesin’s motor-attachment rate and that different tau isoforms have different effects. They do not compare tau-mediated inhibition across kinesin-1, kinesin-2, kinesin-3, and dynein, so the claimed ranking of motor sensitivity is not supported by our copy. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites McVicker et al., 2011 sourcePartly supported

  The Results (page unavailable) show that tau inhibits kinesin run length, with the degree of inhibition differing between tau isoforms. The cited paper does not establish the claimed comparison among kinesin-1, kinesin-3, kinesin-2, and dynein; searches for those motor classes and dynein found no such comparison. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Kinesin-1 and kinesin-3 are major drivers of anterograde transport in axons, trafficking endosomes, lysosomes, mRNA, and other cargoes.

“Kinesin-1 and kinesin-3 are major drivers of anterograde transport in axons, trafficking endosomes, lysosomes, mRNA, and other cargoes (Jenkins et al., 2012; Beaudet et al., 2024; Nagpal et al., 2024).”

• cites Jenkins et al., 2012 sourcePartly supported

  The Discussion (page unavailable) describes KIF1A, a kinesin-3 motor, as a principal motor for axonal transport of synaptic vesicle proteins and notes that a kinesin-1 motor transports some axonal cargoes. The Introduction broadly includes RNA complexes among kinesin cargoes, but the paper does not establish that kinesin-1 and kinesin-3 are major axonal drivers of endosomes, lysosomes, and mRNA specifically. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites Beaudet et al., 2024 sourcePartly supported

  The paper’s introductory passage (indexed under Abstract; page unavailable) identifies kinesin-1 and kinesin-3 among the principal motors driving anterograde transport and associates them with endosomes and lysosomes. It does not establish the full claim about transport of those cargoes specifically in axons or mention mRNA as a cargo in that passage. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites Nagpal et al., 2024 sourcePartly supported

  The Discussion reports that kinesin-1 and kinesin-3 contribute to endosome and lysosome motility, and the Results describe their role in anterograde lysosome transport. The Introduction mentions mRNA transport by kinesins generally, but the paper does not establish that kinesin-1 and kinesin-3 are major drivers of mRNA trafficking specifically in axons. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

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

Phosphorylation likely also regulates tau-induced lattice compaction, misregulation of which could have downstream effects on microtubule stability and interactions with other MAPs and motor proteins.

“Phosphorylation likely also regulates tau-induced lattice compaction (Siahaan et al., 2022), in which misregulation of this process could have downstream effects on microtubule stability, as well as interactions with other MAPs and motor proteins.”

• cites Siahaan et al., 2022 sourcePartly supported

  The Results section, “Tau cooperativity by local microtubule lattice compaction” (page unavailable), reports that lattice regions covered by tau envelopes compacted. Our copy does not establish that phosphorylation regulates this tau-induced compaction; a search for phosphorylation found no passage addressing that link. The proposed downstream effects are the citing authors’ inference, not the part directly attributed to this source. (LLM, conf=0.83)

  Experimental — accuracy not yet measured

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

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

MAP7 competes with tau for lattice occupancy and has been shown to enhance kinesin-1 motility while inhibiting kinesin-3.

“MAP7 competes with tau for lattice occupancy and has been shown to enhance kinesin-1 motility while inhibiting kinesin-3”

• cites Monroy et al., 2018 sourceSupported

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

Teams of motors that transport cargo have distinct functions, including force-producing motors and others that act primarily as tethers.

“teams of motors that transport cargo have distinct functions (Nagpal et al., 2024), including force-producing motors and others that act primarily as tethers”

• cites Nagpal et al., 2024 sourceSupported
• cites Feng et al., 2018 sourceSupported
• cites Arpağ et al., 2019 sourceSupported

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

The pathogenic R5L mutation in the phosphatase-activating domain (PAD) disrupts cooperative binding by altering the structure of the N-terminal projection domain without affecting the microtubule-binding repeats or tau's microtubule affinity.

“the pathogenic R5L mutation in the phosphatase-activating domain (PAD) disrupts cooperative binding by altering the structure of the N-terminal projection domain without affecting the microtubule-binding repeats or tau's microtubule affinity”

• cites Cario et al., 2022 sourceSupported

May combine two claims.

iPSC-derived neurons at DIV 7-8 predominantly express 3R tau, with 4R tau expression increasing during maturation.

“iPSC-derived neurons at DIV 7–8 predominantly express 3R tau, with 4R tau expression increasing during maturation”

• cites Iovino et al., 2010 sourcePartly supported

  The Results and Discussion (page not available in our copy) report that 3R tau appears early and 4R tau increases with maturation. But the studied neurons were derived from human embryonic or fetal stem cells, not iPSCs; the paper therefore does not establish the claimed pattern in iPSC-derived neurons at DIV 7–8. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites Iovino et al., 2015 sourcePartly supported

  The Results section (‘Expression of tau isoforms in human IPSC-derived neurons’; page unavailable) supports the developmental pattern in control and P301L cells: 3R tau mRNA is present from Day 1, while 4R tau mRNA appears at Day 30 and 4R protein is detected later. It does not establish predominant 3R protein expression specifically at DIV 7–8. It also reports that N279K cells express both 3R and 4R tau mRNA from Day 1, so the claim does not apply uniformly to the studied iPSC-derived neurons. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites Sposito et al., 2015 sourcePartly supported

  The Results sections on tau expression and postnatal splicing (page unavailable) report only 3R tau in control iPSC-derived neurons through Day 100, followed by both 3R and 4R tau at Day 365. They do not report tau isoforms at DIV 7–8; the earliest reported detection is tau mRNA at Day 20 and protein at Day 30. Thus, the maturation pattern is supported, but the specific DIV 7–8 claim is not. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

May combine two claims.

The transport effects of tau hyperphosphorylation are determined not only by changes in tau-motor interactions but also by cargo-specific motor compositions and their differential sensitivities to tau.

“the transport effects of tau hyperphosphorylation are determined not only by changes in tau-motor interactions but also by cargo-specific motor compositions and their differential sensitivities to tau”

• cites Beaudet et al., 2024 sourcePartly supported

  The Results and Discussion (page unavailable) show that cargoes carry different sets of motors and respond differently to tau. The Discussion predicts that posttranslational changes to tau could have cargo-specific transport effects, but the paper does not establish effects of tau hyperphosphorylation specifically or attribute them to changed tau–motor interactions. (LLM, conf=0.87)

  Experimental — accuracy not yet measured

May combine two claims.

3R tau has a lower affinity for microtubules but more strongly inhibits kinesin and dynein motors compared to 4R tau.

“3R tau has a lower affinity for microtubules but more strongly inhibits kinesin and dynein motors compared to 4R tau”

• cites Vershinin et al., 2008 sourceNot checked — no full text of the source
• cites McVicker et al., 2011 sourcePartly supported

  The Results (page unavailable) report that 3RS-Tau inhibited kinesin run lengths more than 4RL-Tau on paclitaxel-stabilized microtubules. The paper does not report that 3R tau has lower microtubule affinity than 4R tau or that it more strongly inhibits dynein; its affinity comparison concerns different microtubule preparations, not a 3R-versus-4R difference. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites McVicker et al., 2014 sourcePartly supported

  The Discussion (page not available) says 3RS-Tau is a more potent inhibitor of kinesin than 4RL-Tau. The Introduction says the isoforms differ in microtubule affinity but does not specify which has lower affinity; the passages found do not address comparative inhibition of dynein. Thus only the kinesin part is supported. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

May combine two claims.

Mutations at Y18 increase tau dynamics on microtubules, reduce tau accumulation, and impair tau-mediated regulation of intracellular transport.

“mutations at Y18, the terminal residue of PAD, increase tau dynamics on microtubules, reduce tau accumulation, and impair tau-mediated regulation of intracellular transport”

• cites Kanaan et al., 2012 sourcePartly supported

  Results §3.2 reports that phosphorylation at Y18 prevents tau filaments from inhibiting fast axonal transport, supporting the transport portion of the claim. The cited passages do not show that mutations at Y18 increase tau dynamics on microtubules or reduce tau accumulation; the paper tests Y18 phosphorylation rather than establishing those effects of Y18 mutations. No page numbers are available in our copy. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites Stern et al., 2017 sourcePartly supported

  The Results report that the Y18E phosphomimetic shifts 3RS-Tau toward dynamic binding on microtubules and reduces its inhibition of kinesin-1 motility. The Discussion also reports less Y18E Tau bound to microtubules, which may explain “reduced accumulation” if that means reduced microtubule binding. The claim overgeneralizes these findings to Y18 mutations as a group and to intracellular transport broadly; the motility experiment measured kinesin-1 in vitro. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites Balabanian et al., 2022 sourcePartly supported

  The Introduction (page unavailable) reports that phosphomimetic Y18E tau has reduced microtubule affinity and increased diffusivity, while the Discussion proposes that a negative charge at Y18 may favor dynamic microtubule binding. The Results (page unavailable) show reduced tau-mediated inhibition of lysosome transport at low Y18E expression, but stronger inhibition of early-endosome motility; the effect on transport is therefore cargo-dependent. Our copy does not establish reduced tau accumulation, and it presents the proposed change in binding dynamics more cautiously than the claim. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

May combine two claims.

Our results are consistent with a tug-of-war mechanism, in which tau acts as a selective barrier that preferentially inhibits kinesins-1 and -3, thereby shifting the balance toward dynein-driven transport.

“Our results are consistent with a tug-of-war mechanism, in which tau acts as a selective barrier that preferentially inhibits kinesins-1 and -3, thereby shifting the balance toward dynein-driven transport”

• cites Müller et al., 2008 sourcePartly supported

  The Discussion (p. 6) supports tug-of-war as a mechanism for bidirectional transport, and the Results (p. 5) show that changes in motor properties can shift the direction of transport. Our copy does not identify tau as a selective barrier or report preferential inhibition of kinesins-1 and -3, so it does not support that specific explanation for a shift toward dynein-driven transport. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites Chaudhary et al., 2018 sourcePartly supported

  The Discussion (page unavailable) says tau preferentially inhibits kinesin on bidirectional cargoes, reducing opposing force and shifting transport toward the microtubule minus end. The Results section on motor-specific tuning (page unavailable) examines kinesin-1 and kinesin-2 with dynein, not preferential inhibition of kinesin-3. The specific claim about kinesin-3 is therefore unsupported by this paper. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites Beaudet et al., 2024 sourcePartly supported

  The paper describes tau as a selective barrier and says kinesins-1 and -3 are more sensitive to it than dynein (background passage; page unavailable). The Results report minus-end–biased transport for bidirectional cargoes, consistent with a shift toward dynein, but also strong inhibition of retrograde cargoes. The claim omits this cargo-dependent qualification and implies a general shift toward dynein-driven transport. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

May combine two claims.

DIV7-8 iPSC-derived neurons predominantly express 3R tau, whereas our rescue experiments used 4R0N tau.

“DIV7–8 iPSC-derived neurons predominantly express 3R tau (Iovino et al., 2010; Iovino et al., 2015; Sposito et al., 2015), whereas our rescue experiments used 4R0N tau”

• cites Iovino et al., 2010 sourcePartly supported

  The Results section, “Adult human brain tau isoforms are expressed in hESC-derived neurons” (page unavailable), reports 3R tau mRNA at 7 DIV, with 4R tau appearing later. But the study used embryonic stem cell-derived neurons, not iPSC-derived neurons, and detected 3R tau protein only from 14 DIV; it does not establish predominant 3R tau protein expression at DIV7–8 in iPSC-derived neurons. The statement about the citing authors’ rescue experiments is their own, not a finding attributed to this source. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites Iovino et al., 2015 sourcePartly supported

  The Results section, “Expression of tau isoforms in human IPSC-derived neurons” (page unavailable), reports 3R tau mRNA from Day 1 in control and P301L cells, with 4R mRNA appearing at Day 30. It does not establish the tau-protein isoform balance specifically at DIV7–8, and N279K cells expressed both 3R and 4R mRNA from Day 1. The cited paper is not offered as evidence for the citing authors’ own 4R0N rescue experiments. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites Sposito et al., 2015 sourcePartly supported

  The Results section reports that control iPSC-derived cortical neurons expressed 3R tau from Day 20 through Day 100 of differentiation, supporting the predominant-3R point. It does not establish tau expression at DIV7–8. The statement about the citing authors’ rescue experiments is not attributed to this source. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

May combine two claims.

Hallinan et al., 2019 reported lysosome transport defects with E14 tau opposite to those observed here, but their study used more mature hippocampal neurons and observed MC1-positive tau aggregates in axons.

“Hallinan et al., 2019 reported lysosome transport defects with E14 tau opposite to those observed here, but their study used more mature hippocampal neurons and observed MC1-positive tau aggregates in axons”

• cites Hallinan et al., 2019 sourceSupported

May combine two claims.

Prior to oligomerization and late-stage aggregation, hyperphosphorylated tau first impairs transport, which then contributes to axonal decline.

“prior to oligomerization and late-stage aggregation, hyperphosphorylated tau first impairs transport, which then contributes to axonal decline”

• cites Moretto et al., 2026 sourcePartly supported

  The Discussion (page not provided) reports transport deficits in mice with highly phosphorylated mutant tau before overt aggregation, and links tau phosphorylation to those deficits. It suggests that impaired transport contributes to neurodegeneration, but does not establish that it causes subsequent axonal decline or that the deficits precede oligomerization specifically. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

May combine two claims.

AP tau formed more robust envelopes, with a similar mean width of 1.70 ± 0.09 μm, but covering 40.6 ± 2.1% of microtubules, and a higher enrichment of 1.77 ± 0.18.

“AP tau formed more robust envelopes, with a similar mean width of 1.70 ± 0.09 μm, but covering 40.6 ± 2.1% of microtubules, and a higher enrichment of 1.77 ± 0.18.”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

Hyperphosphorylated tau weakens tau-mediated regulation of lysosome transport, mimicking tau knockout neurons that exhibit enhanced processivity.

“While phospho-resistant tau inhibits processive lysosome motility, hyperphosphorylated tau weakens tau-mediated regulation of lysosome transport, mimicking tau knockout neurons that exhibit enhanced processivity.”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

E14 tau interacts more diffusely, has altered distribution along the axon, and fails to form envelopes.

“However, E14 tau interacts more diffusely, has altered distribution along the axon, and fails to form envelopes.”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

WT and AP tau mildly inhibit KIF5C motility but increase detachment within envelopes, whereas E14 tau weakens these effects.

“WT and AP tau mildly inhibit KIF5C motility but increase detachment within envelopes, whereas E14 tau weakens these effects.”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

Hyperphosphorylation phenocopies tau knockouts, weakening tau-mediated regulation of lysosome transport, resulting in increased processive motility.

“Rescue assays showed that hyperphosphorylation phenocopies tau knockouts, weakening tau-mediated regulation of lysosome transport, resulting in increased processive motility.”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

WT tau formed envelopes with a mean width of 1.77 ± 0.11 μm, covering 32.0 ± 2.0% of microtubules, and an enrichment ratio of 1.32 ± 0.05.

“WT tau formed envelopes with a mean width of 1.77 ± 0.11 μm, covering 32.0 ± 2.0% of microtubules, and an enrichment ratio of 1.32 ± 0.05.”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

Using in vitro reconstitution and live-cell imaging in iPSC-derived neurons, disease-associated hyperphosphorylation alters tau dynamics on microtubules and impairs intracellular transport.

“Using in vitro reconstitution and live-cell imaging in iPSC-derived neurons, we find that disease-associated hyperphosphorylation alters tau dynamics on microtubules and impairs intracellular transport.”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

WT and AP tau bind microtubules cooperatively, forming envelopes both in vitro and in live neurons.

“Our results show that WT and AP tau bind microtubules cooperatively, forming envelopes both in vitro and in live neurons.”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

Low expression of E14 tau increased long-range lysosome transport but was reduced at high expression levels, although to a lesser extent than in neurons expressing WT or AP tau.

“Low expression of E14 tau increased long-range lysosome transport but was reduced at high expression levels, although to a lesser extent than in neurons expressing WT or AP tau”

May combine two claims.

AP tau recovered more slowly than WT tau, while E14 tau recovered the fastest (WTτ: 4.56 s; APτ: 5.39 s; E14τ: 2.43 s).

“AP tau recovered more slowly than WT tau, while E14 tau recovered the fastest (WTτ: 4.56 s; APτ: 5.39 s; E14τ: 2.43 s) (Figure 2G).”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

Similar to observations in vitro, tau dispersed either diffusively or formed well-defined envelopes in axons.

“Similar to observations in vitro, tau dispersed either diffusively or formed well-defined envelopes in axons (Figure 2A).”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

Effects on long-range lysosome transport were primarily dependent on tau expression level and scaled differently with each phospho-variant.

“the effects on long-range lysosome transport were primarily dependent on tau expression level and scaled differently with each phospho-variant”

May combine two claims.

Envelopes heterogeneously patterned axons and were often clustered in axonal segments several microns in length between segments of axons with diffuse tau signal.

“Envelopes heterogeneously patterned axons and were often clustered in axonal segments several microns in length between segments of axons with diffuse tau signal”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

AP tau expression resulted in fewer lysosomes that were distributed more evenly across axonal regions.

“AP tau expression resulted in fewer lysosomes that were distributed more evenly across axonal regions”

May combine two claims.

In MAPT-KO neurons expressing WT tau, lysosome frequency was reduced compared to control neurons, but were marginally enriched in the proximal axon.

“In MAPT-KO neurons expressing WT tau, lysosome frequency was reduced compared to control neurons, but were marginally enriched in the proximal axon”

May combine two claims.

E14 tau had reduced enrichment frequencies within discrete regions (0.11±0.03), and these regions were rarely observed throughout axons (20.3 ± 4.9%).

“In contrast, E14 tau had reduced enrichment frequencies within discrete regions (E14: 0.11±0.03), and these regions were rarely observed throughout axons (E14: 20.3 ± 4.9%)”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

Tau reduced the mean run lengths and velocities of KIF5C relative to mock conditions but with minimal differences among the phospho-variants.

“In addition, tau reduced the mean run lengths and velocities relative to mock conditions but with minimal differences among the phospho-variants ([mock: 1.91 ± 0.10 μm; WT: 1.59 ± 0.12 μm; AP: 1.51 ± 0.09 μm; E14: 1.62 ± 0.09 μm], [mock: 0.94 ± 0.04 μm/s; WT: 0.81 ± 0.04 μm/s; AP: 0.88 ± 0.03 μm/s; E14: 0.83 ± 0.04 μm/s])”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

E14 tau localized to microtubules but did not show sharp boundaries between envelopes and gaps.

“In contrast, E14 tau localized to microtubules but did not show sharp boundaries between envelopes and gaps.”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

E14 tau envelopes were not detected on GMPCPP microtubules and were significantly reduced on taxol-stabilized microtubules (MTtaxol: 0.13 ± 0.02 μm−1), and showed a reduced bound fraction (MTGMPCPP: 1.03 ± 0.01 vs MTtaxol: 1.11 ± 0.01).

“E14 tau envelopes were not detected on GMPCPP microtubules and were significantly reduced on taxol-stabilized microtubules (MTtaxol: 0.13 ± 0.02 μm⁻¹), as well as showed a reduced bound fraction (MTGMPCPP: 1.03 ± 0.01 vs MTtaxol: 1.11 ± 0.01)”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

E14 tau exhibited the lowest mean envelope width of 1.40 ± 0.10 μm, reduced microtubule coverage of 18.3 ± 2.1%, and a minimal enrichment of 1.13 ± 0.02.

“E14 tau exhibited the lowest mean envelope width of 1.40 ± 0.10 μm, reduced microtubule coverage of 18.3 ± 2.1%, and a minimal enrichment of 1.13 ± 0.02 (Figure 1D–F).”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

KIF1A dissociation rate increased substantially in the presence of tau, with E14 tau having the highest increase followed by WT, then AP tau.

“the dissociation rate of KIF1A increased substantially in the presence of tau, with E14 tau having the highest increase followed by WT, then AP tau”

May combine two claims.

KIF5C dissociation rates were similar on tau-free microtubules and in the presence of E14 tau, but were slightly higher with WT tau and AP tau.

“KIF5C dissociation rates were similar on tau-free microtubules and in the presence of E14 tau, but were slightly higher with WT tau and AP tau”

May combine two claims.

E14 tau expression increased mean displacements, similar to MAPT-KO neurons.

“E14 tau expression increased mean displacements, similar to MAPT-KO neurons”

May combine two claims.

During each 2-min timelapse sequence, lysosomes were predominantly immotile or exhibited short, diffusive trajectories, while only a small fraction of total transport was directed.

“During each 2-min timelapse sequence, lysosomes were predominantly immotile or exhibited short, diffusive trajectories, while only a small fraction of total transport was directed”

May combine two claims.

WT and AP tau formed envelopes with comparable enrichment intensity (WT: 1.29 ± 0.003 vs AP: 1.32 ± 0.002) and mean width (WT: 2.28 ± 0.22 μm vs AP: 2.27 ± 0.21 μm).

“Quantification showed that WT and AP tau formed envelopes with comparable enrichment intensity (WT: 1.29 ± 0.003 vs AP: 1.32 ± 0.002) and mean width (WT: 2.28 ± 0.22 μm vs AP: 2.27 ± 0.21 μm).”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

KIF5C detached more frequently inside of WT and AP tau envelopes than outside, whereas the detachment frequency was similar inside and outside of regions of increased E14 tau intensity.

“However, KIF5C detached more frequently inside of WT and AP tau envelopes than outside, whereas the detachment frequency was similar inside and outside of regions of increased E14 tau intensity”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

WT tau displayed an envelope frequency of 0.07 ± 0.02 μm−1 on GMPCPP microtubules vs 0.18 ± 0.01 μm−1 on taxol microtubules, and a lower bound fraction (MTGMPCPP: 1.12 ± 0.01 vs MTtaxol: 1.32 ± 0.03).

“WT tau displayed an envelope frequency of 0.07 ± 0.02 μm⁻¹ on GMPCPP microtubules vs 0.18 ± 0.01 μm⁻¹ on taxol microtubules, and a lower bound fraction (MTGMPCPP: 1.12 ± 0.01 vs to MTtaxol: 1.32 ± 0.03)”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

AP tau exhibited a higher frequency of envelopes within discrete regions compared to WT tau (WT: 0.16 ± 0.02 vs AP: 0.22 ± 0.02), and a greater percentage of axons contained envelope-positive segments (WT: 35.6 ± 4.5% vs AP: 47.9 ± 4.3%).

“AP tau exhibited a higher frequency of envelopes within discrete regions compared to WT tau (WT: 0.16 ± 0.02 vs AP: 0.22 ± 0.02), as well as a greater percentage of axons contained envelope-positive segments (WT: 35.6 ± 4.5% vs AP: 47.9 ± 4.3%)”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

E14 tau enrichment above thresholds was much less intense (1.14 ± 0.002) and the mean width of these areas was reduced compared to WT and AP tau (1.88 ± 0.24 μm).

“Enrichment above thresholds were detected but were much less intense (E14: 1.14 ± 0.002) and the mean width of these areas were reduced compared to WT and AP tau (E14: 1.88 ± 0.24 μm)”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

With AP tau, the reduction in long-range transport was more pronounced with lower expression levels, and higher expression more strongly reduced anterograde directed transport.

“With AP tau, the reduction in long-range transport was more pronounced with lower expression levels, and higher expression more strongly reduced anterograde directed transport”

May combine two claims.

KIF1A mean run lengths were reduced substantially compared to mock conditions, with E14 tau having the strongest reduction compared to AP and WT tau, but mean velocities remained largely unchanged.

“KIF1A mean run lengths were reduced substantially compared to mock conditions, with E14 tau having the strongest reduction compared to AP and WT tau (mock: 3.48 ± 0.20 μm; WT: 2.30 ± 0.71 μm; AP: 1.96 ± 1.06 μm; E14: 1.66 ± 0.04 μm), but the mean velocities remained largely unchanged”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

In COS-7 cells, WT and AP tau showed clear microtubule enrichment as the fluorescence signal along microtubules recovered above cytosolic levels, while E14 tau showed no microtubule enrichment.

“Furthermore, in COS-7 cells, WT and AP tau showed clear microtubule enrichment as the fluorescence signal along microtubules recovered above cytosolic levels, while E14 tau showed no microtubule enrichment, consistent with our in vitro data showing reduced microtubule enrichment”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

WT and AP tau are more enriched proximally than E14 tau, which is more uniformly distributed along the axon.

“We found that WT and AP tau are more enriched proximally than E14 tau, which is more uniformly distributed along the axon (Figure 2I).”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

Tau binds microtubules cooperatively to form cohesive envelopes in live neurons, consistent with its behavior on stabilized microtubules in vitro.

“Tau binds microtubules cooperatively to form cohesive envelopes in live neurons, consistent with its behavior on stabilized microtubules in vitro”

May combine two claims.

Disease-related hyperphosphorylation prevents cooperative binding and enhances tau's dissociation from microtubules.

“Disease-related hyperphosphorylation prevents cooperative binding and enhances tau's dissociation from microtubules”

May combine two claims.

Phospho-mimetic mutations significantly reduced cooperative envelope formation and increased tau dissociation from microtubules, indicating weakened microtubule affinity.

“phospho-mimetic mutations significantly reduced cooperative envelope formation and increased tau dissociation from microtubules, indicating weakened microtubule affinity”

May combine two claims.

Phospho-resistant tau reduced anterograde transport with little effect on retrograde transport, whereas hyperphosphorylated tau relieved inhibition of anterograde transport and enhanced retrograde transport.

“Phospho-resistant tau reduced anterograde transport with little effect on retrograde transport, whereas hyperphosphorylated tau relieved inhibition of anterograde transport and enhanced retrograde transport”

May combine two claims.

Hyperphosphorylation reduces KIF5C dissociation from microtubules, while it increases that of KIF1A.

“Hyperphosphorylation reduces KIF5C dissociation from microtubules, while it increases that of KIF1A”

May combine two claims.

E14 tau expression caused a marginal increase in anterograde processive run lengths and velocities, while significantly enhancing retrograde processivity.

“E14 tau expression caused a marginal increase in anterograde processive run lengths and velocities, while significantly enhancing retrograde processivity”

May combine two claims.

Although kinesin-3 was strongly inhibited by tau overall, hyperphosphorylated tau produced a greater inhibitory effect, as evidenced by accelerated motor detachment in regions of elevated E14 tau intensity along microtubules.

“although kinesin-3 was strongly inhibited by tau overall (Figure 3C, D), hyperphosphorylated tau produced a greater inhibitory effect, as evidenced by accelerated motor detachment in regions of elevated E14 tau intensity along microtubules”

May combine two claims.

AP tau reduced anterograde processive transport, as reflected by shorter run lengths and lower velocities.

“AP tau reduced anterograde processive transport, as reflected by shorter run lengths (APant: 3.10 ± 0.35 μm vs WTant: 3.93 ± 0.83 μm) and lower velocities (APant: 0.80 ± 0.15 μm/s vs WTant: 0.95 ± 0.17 μm/s)”

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

Lysosome transport in WT 4R tau-expressing MAPT-KO neurons was indifferent from controls.

“lysosome transport in WT 4R tau-expressing MAPT-KO neurons was indifferent from controls”

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

Microtubules with tau envelopes were identified by multi-component Gaussian mixture model fits, whereas those lacking envelopes were best fit by a single-component model.

“Microtubules with tau envelopes were identified by multi-component fits, whereas those lacking envelopes were best fit by a single-component model (Figure 1C).”

May combine two claims.

Disease-related hyperphosphorylation weakens the formation of cooperatively-bound tau envelopes on microtubules and perturbs tau-mediated regulation of degradative organelles, which would be expected to cause defects in cargo maturation and protein homeostasis, contributing to neurodegeneration.

“Combined, our results demonstrate how disease-related hyperphosphorylation weakens the formation of cooperatively-bound tau envelopes on microtubules and perturbs tau-mediated regulation of degradative organelles, which would be expected to cause defects in cargo maturation and protein homeostasis, contributing to neurodegeneration.”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

In Alzheimer's disease and other tauopathies, tau becomes abnormally hyperphosphorylated, reducing its microtubule affinity and promoting aggregation.

“In Alzheimer’s disease and other tauopathies, tau becomes abnormally hyperphosphorylated, reducing its microtubule affinity and promoting aggregation (Schneider et al., 1999; Cho and Johnson, 2004).”

• cites Schneider et al., 1999 sourceNot checked — no full text of the source
• cites Cho and Johnson, 2004 sourceNot checked — no full text of the source

May combine two claims.

Tau hyperphosphorylation disrupts cooperative microtubule binding and dysregulates lysosome transport.

“Using tau phospho-variants in vitro and in live neurons, we show that tau hyperphosphorylation disrupts cooperative microtubule binding and dysregulates lysosome transport.”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

Classified as probably not a substantial claim.

Tau envelopes act as selective, reversible barriers along microtubules, regulating the access of motor proteins and other MAPs to the microtubule.

“Tau envelopes act as selective, reversible barriers along microtubules, regulating the access of motor proteins and other MAPs to the microtubule.”

• cites Dixit et al., 2008 sourceNot checked — no full text of the source

May combine two claims.

Hyperphosphorylation disrupts tau envelopes and impairs lysosome trafficking, likely contributing to early defects in degradative pathways that drive neurodegeneration.

“Altogether, these findings show that hyperphosphorylation disrupts tau envelopes and impairs lysosome trafficking, likely contributing to early defects in degradative pathways that drive neurodegeneration.”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

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

These effects would likely become more pronounced over longer timescales and in more mature or aged neurons.

“These effects would likely become more pronounced over longer timescales and in more mature or aged neurons”

May combine two claims.

Phosphorylation influences not only cooperativity but also modulates tau's direct binding to microtubules.

“Together, these results indicate that phosphorylation influences not only cooperativity but also modulates tau’s direct binding to microtubules.”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

Hyperphosphorylation disrupts tau's cooperative microtubule binding in neurons, preventing the formation of envelopes along microtubules, increasing exchange between microtubules and the cytosol, and altering tau distribution throughout axons.

“Altogether, these results suggest that hyperphosphorylation disrupts tau’s cooperative microtubule binding in neurons, preventing the formation of envelopes along microtubules, increasing exchange between microtubules and the cytosol, and altering tau distribution throughout axons (Figure 2I).”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

May combine two claims.

Lysosomes are normally slightly enriched in the proximal axon and tau promotes lysosome flux toward this region.

“lysosomes are normally slightly enriched in the proximal axon and that tau promotes lysosome flux toward this region”

May combine two claims.

Tau hyperphosphorylation appears to weaken its inhibitory effect on kinesin-1 while maintaining or enhancing its suppression of kinesin-3.

“tau hyperphosphorylation appears to weaken its inhibitory effect on kinesin-1 while maintaining or enhancing its suppression of kinesin-3”

May combine two claims.

Hyperphosphorylation may weaken tau's ability to regulate motor engagement and thereby contribute to axonal transport defects.

“Thus, hyperphosphorylation may weaken tau’s ability to regulate motor engagement and thereby contribute to axonal transport defects.”

• AssumptionThe authors state this as an assumption: E14 tau mimics hyperphosphorylation and AP tau prevents phosphorylation at the 14 mutated residues.

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

Tau misregulation might disrupt lysosome localization by enhancing long-range retrograde transport, and therefore degradative pathways.

“Tau misregulation might disrupt lysosome localization by enhancing long-range retrograde transport, and therefore degradative pathways”

May combine two claims.

KIF5C is less inhibited by E14 tau, whereas KIF1A is less inhibited by AP tau, at comparable local intensities.

“KIF5C is less inhibited by E14 tau, whereas KIF1A is less inhibited by AP tau, at comparable local intensities”

May combine two claims.

AP tau reduced directional switching and is more inhibitory to anterograde-directed processive motility.

“AP tau reduced directional switching and is more inhibitory to anterograde-directed processive motility”

May combine two claims.

Modifications within the N-terminal projection domain, either in PAD or the proline-rich region, as well as the C-terminal pseudo-repeat domain can alter tau-microtubule interactions and, consequently, tau's ability to regulate intracellular transport.

“modifications within the N-terminal projection domain, either in PAD or the proline-rich region, as well as the C-terminal pseudo-repeat domain can alter tau-microtubule interactions and, consequently, tau's ability to regulate intracellular transport”

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

Kinesin-1 and kinesin-3 are more sensitive to inhibition by tau, whereas kinesin-2 and dynein are comparatively less affected.

“Previous single-molecule studies showed that kinesin-1 and kinesin-3 are more sensitive to inhibition by tau, whereas kinesin-2 and dynein are comparatively less affected”

May combine two claims.

Hyperphosphorylation disrupts tau's ability to form envelopes on microtubules and alters microtubule-based transport.

“hyperphosphorylation disrupts tau's ability to form envelopes on microtubules and alters microtubule-based transport”

May combine two claims.

The approaches enabled us to examine tau function in a near-physiological environment, preserving relevant mammalian cytosolic factors and PTMs, while isolating the effects of hyperphosphorylation of a single tau isoform.

“These approaches enabled us to examine tau function in a near-physiological environment, preserving relevant mammalian cytosolic factors and PTMs, while isolating the effects of hyperphosphorylation of a single tau isoform”

May combine two claims.

Changes in tau phosphorylation alter the balance of directed lysosome transport, leading to altered lysosome flux and distribution along axons.

“changes in tau phosphorylation alter the balance of directed lysosome transport, leading to altered lysosome flux and distribution along axons”

May combine two claims.

E14 tau alleviated this inhibition and enhanced retrograde processivity, resembling tau knockout conditions.

“E14 tau alleviated this inhibition and enhanced retrograde processivity, resembling tau knockout conditions”

May combine two claims.

Lysosome motility is driven by multiple motor types, and the transport phenotypes observed here likely reflect the combined contributions of kinesins-1, -2, -3, and dynein.

“Lysosome motility is driven by multiple motor types, and the transport phenotypes observed here likely reflect the combined contributions of kinesins-1, -2, -3, and dynein”

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

The sensitivity of kinesin homologs to tau regulation likely varies due to differences in their intrinsic motor properties.

“the sensitivity of kinesin homologs to tau regulation likely varies due to differences in their intrinsic motor properties”

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

Hyperphosphorylation may have more severe effects in mature neurons where 3R and 4R tau are equally expressed.

“hyperphosphorylation may have more severe effects in mature neurons where 3R and 4R tau are equally expressed”

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

These opposing effects could enhance anterograde transport through increased kinesin-1 processivity or promote retrograde transport by limiting kinesin-3 activity, while having a comparatively minor impact on dynein-mediated transport.

“These opposing effects could enhance anterograde transport through increased kinesin-1 processivity or promote retrograde transport by limiting kinesin-3 activity, while having a comparatively minor impact on dynein-mediated transport”

May combine two claims.

Disruptions in transport result in altered lysosome flux along the axon, likely lead to impairments of degradative pathways and protein homeostasis, which contribute to neuronal dysfunction and degeneration in tauopathies.

“These disruptions in transport, which result in altered lysosome flux along the axon (Figure 4D), likely lead to impairments of degradative pathways and protein homeostasis, which contribute to neuronal dysfunction and degeneration in tauopathies”

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

Tau is phosphorylated at numerous residues and at different developmental stages, and individual tau molecules often exhibit heterogeneous phosphorylation patterns.

“Tau is phosphorylated at numerous residues and at different developmental stages, and individual tau molecules often exhibit heterogeneous phosphorylation patterns”

• cites Lindwall and Cole, 1984 sourceNot checked — no full text of the source
• cites Mandelkow et al., 1995 sourceNot checked — no full text of the source
• cites Trinczek et al., 1995 sourceNot checked — no full text of the source

May combine two claims.

Hyperphosphorylated tau alleviates this inhibition and enhances retrograde directed transport, mimicking tau knockout conditions.

“hyperphosphorylated tau alleviates this inhibition and enhances retrograde directed transport, mimicking tau knockout conditions”

May combine two claims.

Enhanced detachment of kinesin-3 by hyperphosphorylated tau could reduce its tethering capacity, shifting the balance of forces in favor of dynein-driven retrograde transport.

“enhanced detachment of kinesin-3 by hyperphosphorylated tau could reduce its tethering capacity, shifting the balance of forces in favor of dynein-driven retrograde transport”

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

Disease phenotypes in mature or patient-derived neurons may be more pronounced and involve additional regulatory mechanisms not captured in this system.

“disease phenotypes in mature or patient-derived neurons may be more pronounced and involve additional regulatory mechanisms not captured in this system”

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

Phosphorylation at different sites may differentially regulate tau function.

“phosphorylation at different sites may differentially regulate tau function”

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

Isoform-specific differences may influence the magnitude of phosphorylation-dependent effects, particularly in mature neurons where 3R and 4R tau isoforms are co-expressed.

“isoform-specific differences may influence the magnitude of phosphorylation-dependent effects, particularly in mature neurons where 3R and 4R tau isoforms are co-expressed”

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

COS-7 cells used in the study are checked annually for mycoplasma contamination.

“Cells are checked annually for mycoplasma contamination.”

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

Fluorescence recovery curves were background-corrected to account for acquisition-related photobleaching.

“Fluorescence recovery curves were generated using ImageJ and background-corrected to account for acquisition-related photobleaching.”

Classified as probably not a substantial claim.

The optimal number of components in each tau intensity distribution was selected based on the Bayesian Information Criterion.

“The optimal number of components in each distribution was selected based on the Bayesian Information Criterion.”

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

The iPSCs were characterized to ensure correct genotyping and pluripotency, and were screened for microbiology/virus.

“iPSCs were characterized to ensure correct genotyping, pluripotency, and screened for microbiology/virus.”

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

The identity of the cell lines obtained from ATCC and the C-BIG repository was not verified.

“The identity of the cell lines obtained from ATCC and the C-BIG repository (Montreal Neurological Institute-Hospital, Montreal, QC, Canada) were not verified.”

May combine two claims.

The iPSC-derived neurons used here correspond to an early developmental stage and are more similar to embryonic or immature neurons than the aged neurons affected in Alzheimer's disease and other tauopathies.

“The iPSC-derived neurons used here correspond to an early developmental stage and are more similar to embryonic or immature neurons than the aged neurons affected in Alzheimer's disease and other tauopathies”

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

MAPT knockout in the iPSC line was achieved by CRISPR-Cas9 and verified by PCR and sequencing.

“MAPT knockout was achieved by CRISPR–Cas9 and verified by PCR and sequencing.”

May combine two claims.

The findings may reflect distinct stages of pathology, with our results capturing early effects of hyperphosphorylation on tau-microtubule interactions prior to aggregation, whereas later-stage oligomerization and aggregation may impair transport by clogging axons.

“the findings may reflect distinct stages of pathology, with our results capturing early effects of hyperphosphorylation on tau–microtubule interactions prior to aggregation, whereas later-stage oligomerization and aggregation may impair transport by clogging axons”

May combine two claims.

Tauopathy-related hyperphosphorylation weakens tau's interaction with microtubules, reducing its ability to form cohesive envelopes and regulate axonal transport.

“tauopathy-related hyperphosphorylation weakens tau's interaction with microtubules, reducing its ability to form cohesive envelopes and regulate axonal transport”

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

This disruption likely affects signaling and other maintenance pathways essential for axonal health and function.

“this disruption likely affects signaling and other maintenance pathways essential for axonal health and function”

May combine two claims.

As aggregation progresses, these effects are amplified, leading to further trafficking defects, axonal blockages, inflammation, and ultimately neurodegeneration.

“As aggregation progresses, these effects are amplified, leading to further trafficking defects, axonal blockages, inflammation, and ultimately neurodegeneration”

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

Disease-associated phosphorylation is likely more heterogeneous and dynamic than the pseudo-phosphorylation mutants used here.

“disease-associated phosphorylation is likely more heterogeneous and dynamic than the pseudo-phosphorylation mutants used here”

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

COS-7 cells provide a robust mammalian expression system for tau and kinesins, but they lack the full complement of neuronal regulatory factors and organization that shape MAP and motor behavior in neurons.

“while COS-7 cells provide a robust mammalian expression system for tau and kinesins, they lack the full complement of neuronal regulatory factors and organization that shape MAP and motor behavior in neurons”

Probably not a substantial claim: may not pass S2 (checkable).

Our experimental systems enable precise mechanistic dissection of tau-microtubule and tau-motor interactions.

“our experimental systems enable precise mechanistic dissection of tau-microtubule and tau–motor interactions”