Different tau epitopes define Abeta42-mediated tau insolubility.

Division of Psychiatry Research, University of Zürich, August Forel Street 1, 8008 Zürich, Switzerland.
Biochemical and Biophysical Research Communications (Impact Factor: 2.28). 01/2006; 337(4):1097-101. DOI: 10.1016/j.bbrc.2005.09.168
Source: PubMed

ABSTRACT Alzheimer's disease (AD) is characterized by extracellular beta-amyloid (Abeta(42))-containing plaques and intracellular neurofibrillary tangles. The latter are composed of hyperphosphorylated filamentous aggregates of the microtubule-associated protein tau. Previously we demonstrated pathological interactions between these two histopathological hallmarks using human SH-SY5Y neuroblastoma cells overexpressing wild-type and mutant forms of human tau. Exposure to pre-aggregated forms of Abeta(42) caused both the formation of AD-like tau-containing filaments and a decreased solubility of tau, both of which were prevented by mutating the S422 phospho-epitope of tau. Here, we expressed additional tau mutants in SH-SY5Y cells to assess the role of phosphorylation and cleavage sites of tau in tau aggregation. We found that the Abeta(42)-mediated decrease in tau solubility depends on the interplay of distinct phospho-epitopes of tau and not only on phosphorylation of the S422 epitope.

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