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Oligomerization of the microtubule‐associated protein tau is mediated by its N‐terminal sequences: implications for normal and pathological tau action
Author(s) -
Feinstein H. Eric,
Benbow Sarah J.,
LaPointe Nichole E.,
Patel Nirav,
Ramachandran Srinivasan,
Do Thanh D.,
Gaylord Michelle R.,
Huskey Noelle E.,
Dressler Nicolette,
Korff Megan,
Quon Brady,
Cantrell Kristi Lazar,
Bowers Michael T.,
Lal Ratnesh,
Feinstein Stuart C.
Publication year - 2016
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/jnc.13604
Subject(s) - neurodegeneration , microtubule , tau protein , chemistry , biophysics , tubulin , function (biology) , peptide , tauopathy , microbiology and biotechnology , biochemistry , biology , alzheimer's disease , medicine , disease , pathology
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 (tau 45–230 ) assembles into heptamers/octamers. Ferguson analyses of denaturing gels demonstrates that tau 45–230 can dimerize even in sodium dodecyl sulfate. Atomic force microscopy reveals multiple levels of oligomerization by both full‐length tau and tau 45–230 . Finally, ion mobility–mass spectrometric analyses of tau 106–144 , 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.The microtubule‐associated protein tau is essential for neuronal development and maintenance, but is also central to Alzheimer's and related dementias. Unfortunately, the molecular mechanisms underlying normal and pathological tau action remain poorly understood. Here, we demonstrate that tau can homo‐oligomerize, providing novel mechanistic models for normal tau action (promoting microtubule growth and bundling, suppressing microtubule shortening) and pathological tau action (poisoning of oligomeric complexes).