Direct force measurements reveal that protein Tau confers short-range attractions and isoform-dependent steric stabilization to microtubules

Chung, Peter J.; Choi, Myung Chul; Miller, Herbert C.; Feinstein, H. Eric; Raviv, Uri; Li, Youli; Wilson, Leslie; Feinstein, Stuart C.; Safinya, Cyrus R.

doi:10.1073/pnas.1513172112

Cited by 43 publications

(52 citation statements)

References 77 publications

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“…Specifically, the long-range interactions between each of the termini and the MTBR are lost. This expansion is compatible with structural studies, which found that both termini of tau extend away from the microtubule surface when bound (46,47). Interestingly, the same type of expansion was observed previously for tau bound to the molecular aggregation inducer, heparin (36), suggesting that the open conformation of tau is important both for function as well as in dysfunction.…”

Section: Discussionsupporting

confidence: 90%

A functional role for intrinsic disorder in the tau-tubulin complex

Melo

Coraor

Alpha-Cobb

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Tau is an intrinsically disordered protein with an important role in maintaining the dynamic instability of neuronal microtubules. Despite intensive study, a detailed understanding of the functional mechanism of tau is lacking. Here, we address this deficiency by using intramolecular single-molecule Förster Resonance Energy Transfer (smFRET) to characterize the conformational ensemble of tau bound to soluble tubulin heterodimers.Tau adopts an open conformation on binding tubulin, in which the long-range contacts between both termini and the microtubule binding region that characterize its compact solution structure are diminished. Moreover, the individual repeats within the microtubule binding region that directly interface with tubulin expand to accommodate tubulin binding, despite a lack of extension in the overall dimensions of this region. These results suggest that the disordered nature of tau provides the significant flexibility required to allow for local changes in conformation while preserving global features. The tubulin-associated conformational ensemble is distinct from its aggregation-prone one, highlighting differences between functional and dysfunctional states of tau. Using constraints derived from our measurements, we construct a model of tubulin-bound tau, which draws attention to the importance of the role of tau's conformational plasticity in function.single-molecule FRET | intrinsically disordered proteins | microtubuleassociated protein | tauopathies | Alzheimer's disease

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Section: Discussionsupporting

confidence: 90%

A functional role for intrinsic disorder in the tau-tubulin complex

Melo

Coraor

Alpha-Cobb

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…Recent work from Chung et al . () provides biophysical evidence for both mechanisms, which are clearly not mutually exclusive. The work presented here provides strong support for the model that tau dimerization/oligomerization could promote regularly spaced and arrayed microtubule bundles (Fig.…”

Section: Discussionmentioning

confidence: 95%

“…However, some models suggest that the projection domain exerts a repulsive force pushing microtubules aside from one another (Lee and Brandt 1992;Marx et al 2000;Mukhopadhyay and Hoh 2001) while other models suggest that the projection domain somehow cross-links microtubules together (Hirokawa et al 1988;Chen et al, 1992;Rosenberg et al 2008). Recent work from Chung et al (2015) provides biophysical evidence for both mechanisms, which are clearly not mutually exclusive. The work presented here provides strong support for the model that tau dimerization/oligomerization could promote regularly spaced and arrayed microtubule bundles (Fig.…”

Section: Oligomerization and Normal Tau Actionmentioning

confidence: 99%

Oligomerization of the microtubule‐associated protein tau is mediated by its N‐terminal sequences: implications for normal and pathological tau action

Feinstein

Benbow

LaPointe

et al. 2016

Journal of Neurochemistry

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Despite extensive structure-function analyses, the molecular mechanisms of normal and pathological tau action remain poorly understood. How does the C-terminal microtubule-binding region regulate microtubule dynamics and bundling? In what biophysical form does tau transfer trans-synaptically from one neuron to another, promoting neurodegeneration and dementia? Previous biochemical/biophysical work led to the hypothesis that tau can dimerize via electrostatic interactions between two N-terminal “projection domains” aligned in an anti-parallel fashion, generating a multivalent complex capable of interacting with multiple tubulin subunits. We sought to test this dimerization model directly. Native gel analyses of full-length tau and deletion constructs demonstrate that the N-terminal region leads to multiple bands, consistent with oligomerization. Ferguson analyses of native gels indicate that an N-terminal fragment (tau45-230) assembles into heptamers/octamers. Ferguson analyses of denaturing gels demonstrates that tau45-230 can dimerize even in SDS. AFM reveals multiple levels of oligomerization by both full-length tau and tau45-230. Finally, ion-mobility mass spectroscopic analyses of tau106-144, a small peptide containing the core of the hypothesized dimerization region, also demonstrate oligomerization. Thus, multiple independent strategies demonstrate that the N-terminal region of tau can mediate higher-order oligomerization, which may have important implications for both normal and pathological tau action.

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“…The NTD has previously been shown to regulate in vitro polymerization of tubulin (9). It is implicated in isoform-dependent spacing of microtubules (24,25), and removal of the NTD both increases the affinity for microtubules as well as results in the presence of large microtubule bundles (9). Here we observed a similar inhibitory effect in binding to soluble tubulin (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The addition of P2 and R' to MTBR fragments increases microtubule binding and stimulates polymerization (9-11, 19, 20, 22, 23). The NTD together with P1 is thought to regulate binding to and spacing of microtubules (9,(24)(25)(26)(27), and mediate interactions with other cellular partners such as signaling proteins [reviewed in (28)] or the plasma membrane (29).…”

Section: Introductionmentioning

confidence: 99%

Regulation of tau’s proline rich region by its N-terminal domain

McKibben

Rhoades

2019

Preprint

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Tau is an intrinsically disordered, microtubule-associated protein with a role in regulating microtubule dynamics. Despite intensive research, the molecular mechanisms of taumediated microtubule polymerization are poorly understood. Here we use single molecule fluorescence to investigate the role of tau's N-terminal domain (NTD) and proline rich region (PRR) in regulating interactions of tau with soluble tubulin. Both fulllength tau isoforms and truncated variants are assayed for their ability to bind soluble tubulin and stimulate microtubule polymerization. We describe a novel role for tau's PRR as an independent tubulin-binding domain with polymerization capacity. In contrast to the relatively weak tubulin interactions distributed throughout the microtubule binding repeats (MTBR), resulting in heterogeneous tau:tubulin complexes, the PRR binds tubulin tightly and stoichiometrically. Moreover, we demonstrate that interactions between the PRR and MTBR are reduced by the NTD through a conserved conformational ensemble. Based on our data, we propose that tau's PRR can serve as a core tubulin-binding domain, while the MTBR enhances polymerization capacity by increasing the local tubulin concentration. The NTD negatively regulates tubulin-binding interactions of both of these domains. This study draws attention to the central role of the PRR in tau function, as well as providing mechanistic insight into tau-mediated polymerization of tubulin. Significance StatementTau is an intrinsically disordered, microtubule associated protein linked to a number of neurodegenerative disorders. Here we identify tau's proline rich region as having autonomous tubulin binding and polymerization capacity, which is enhanced by the flanking microtubule binding repeats. Moreover, we demonstrate that tau's N-terminal domain negatively regulates both binding and polymerization. We propose a novel model for tau-mediated polymerization whereby the proline rich region serves as a core tubulinbinding domain, while the microtubule binding repeats increase the local concentration.Our work draws attention to the importance of the proline rich region and N-terminal domain in tau function, and highlights the proline rich region as a putative target for the development of therapeutics.

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Direct force measurements reveal that protein Tau confers short-range attractions and isoform-dependent steric stabilization to microtubules

Cited by 43 publications

References 77 publications

A functional role for intrinsic disorder in the tau-tubulin complex

A functional role for intrinsic disorder in the tau-tubulin complex

Oligomerization of the microtubule‐associated protein tau is mediated by its N‐terminal sequences: implications for normal and pathological tau action

Regulation of tau’s proline rich region by its N-terminal domain

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