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Parkinson’s Disease
Volume 2011 (2011), Article ID 392180, 12 pages
http://dx.doi.org/10.4061/2011/392180
Research Article

Contribution of Alanine-76 and Serine Phosphorylation in α-Synuclein Membrane Association and Aggregation in Yeasts

Biology Department, Lake Forest College, Box P7, 555 North Sheridan Road, Lake Forest, IL 60045, USA

Received 14 February 2011; Accepted 1 April 2011

Academic Editor: T. M. Dawson

Copyright © 2011 Michael Fiske et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In Parkinson's disease (PD), misfolded and aggregated α-synuclein protein accumulates in degenerating midbrain dopaminergic neurons. The amino acid alanine-76 in α-synuclein and phosphorylation at serine-87 and serine-129 are thought to regulate its aggregation and toxicity. However, their exact contributions to α-synuclein membrane association are less clear. We found that α-synuclein is indeed phosphorylated in fission yeast and budding yeast, the two models that we employed for assessing α-synuclein aggregation and membrane association properties, respectively. Surprisingly, blocking serine phosphorylation (S87A, S129A, and S87A/S129A) or mimicking it (S87D, S129D) altered α-synuclein aggregation in fission yeast. Either blocking or mimicking this phosphorylation increased endomembrane association in fission yeast, but only mimicking it decreased plasma membrane association in budding yeast. Polar substitution mutations of alanine-76 (A76E and A76R) decreased α-synuclein membrane association in budding yeast and decreased aggregation in fission yeast. These yeast studies extend our understanding of serine phosphorylation and alanine-76 contributions to α-synuclein aggregation and are the first to detail their impact on α-synuclein's plasma membrane and endomembrane association.