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Microtubule-associated protein tau, paired helical filaments, and phosphorylation
E M Mandelkow1, J Biernat, G Drewes
1Max-Planck-Unit for Structural Molecular Biology, Hamburg, Germany.
Abstract:
This paper summarizes our recent studies on microtubule-associated protein tau and its pathological state resembling that of the paired helical filaments of Alzheimer's disease. The Alzheimer-like state of tau protein can be identified and analyzed in terms of certain phosphorylation sites and phosphorylation-dependent antibody epitopes. It can be induced by protein kinases which tend to phosphorylate serine or threonine residues followed by a proline; this includes mitogen-activated protein kinase (MAPK) and glycogen-synthase kinase 3 (GSK-3). Both of these are tightly associated with microtubules as well as with paired helical filaments. Structurally, tau appears as a rod-like molecule; it tends to self-associate into dimers whose monomers are antiparallel. Constructs of truncated tau made up of antiparallel dimers of the microtubule binding domain can be assembled into paired helical filaments in vitro.
Insights
Researchers studied the pathological tau protein, a hallmark of Alzheimer's disease. They identified specific phosphorylation sites and kinases that induce this state, crucial for understanding disease mechanisms.
Area of Science:
- Neuroscience
- Biochemistry
- Molecular Biology
Background:
- Microtubule-associated protein tau (tau) is implicated in Alzheimer's disease pathology.
- Paired helical filaments (PHFs) are a key neuropathological feature of Alzheimer's disease, primarily composed of hyperphosphorylated tau.
- Understanding the molecular basis of tau pathology is crucial for developing therapeutic strategies.
Purpose of the Study:
- To characterize the Alzheimer's-like pathological state of tau protein.
- To identify specific phosphorylation sites and epitopes associated with this pathological state.
- To investigate the role of protein kinases, such as mitogen-activated protein kinase (MAPK) and glycogen-synthase kinase 3 (GSK-3), in inducing tau pathology.
Main Methods:
- Analysis of tau protein phosphorylation sites and phosphorylation-dependent antibody epitopes.
- Induction of Alzheimer's-like tau states using specific protein kinases (MAPK, GSK-3).
- Structural analysis of tau and its self-association properties, including in vitro assembly of PHF-like structures from truncated tau constructs.
Main Results:
- The Alzheimer's-like state of tau is defined by specific phosphorylation patterns and antibody recognition sites.
- Protein kinases MAPK and GSK-3, associated with microtubules and PHFs, induce this pathological tau state.
- Tau protein exhibits a rod-like structure and self-associates into antiparallel dimers; truncated tau can form PHF-like structures in vitro.
Conclusions:
- Specific phosphorylation events mediated by kinases like MAPK and GSK-3 are critical for inducing tau pathology resembling Alzheimer's disease.
- The structural properties of tau, including its dimerization and self-association, contribute to the formation of paired helical filaments.
- These findings provide insights into the molecular mechanisms underlying tau aggregation in Alzheimer's disease.