Soper, J.H. et al. -Synuclein induced aggregation of cytoplasmic vesicles in Saccharomyces cerevisiae. Mol. Biol. Cell 19, 1093-1103

Center for Neurodegenerative Disease Research and Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Molecular biology of the cell (Impact Factor: 4.47). 04/2008; 19(3):1093-103. DOI: 10.1091/mbc.E07-08-0827
Source: PubMed


Aggregated alpha-synuclein (alpha-syn) fibrils form Lewy bodies (LBs), the signature lesions of Parkinson's disease (PD) and related synucleinopathies, but the pathogenesis and neurodegenerative effects of LBs remain enigmatic. Recent studies have shown that when overexpressed in Saccharomyces cerevisiae, alpha-syn localizes to plasma membranes and forms cytoplasmic accumulations similar to human alpha-syn inclusions. However, the exact nature, composition, temporal evolution, and underlying mechanisms of yeast alpha-syn accumulations and their relevance to human synucleinopathies are unknown. Here we provide ultrastructural evidence that alpha-syn accumulations are not comprised of LB-like fibrils, but are associated with clusters of vesicles. Live-cell imaging showed alpha-syn initially localized to the plasma membrane and subsequently formed accumulations in association with vesicles. Imaging of truncated and mutant forms of alpha-syn revealed the molecular determinants and vesicular trafficking pathways underlying this pathological process. Because vesicular clustering is also found in LB-containing neurons of PD brains, alpha-syn-mediated vesicular accumulation in yeast represents a model system to study specific aspects of neurodegeneration in PD and related synucleinopathies.

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Available from: Subhojit Roy, Apr 10, 2014
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    • "In addition, large-scale screenings using this simple genetic model have contributed to our understanding of the molecular mechanisms underlying several human diseases [16]. These include Parkinson's disease, for which several yeast models of α-synuclein toxicity have been developed that recapitulate many disease relevant phenotypes such as vesicular trafficking defects, oxidative stress and mitochondrial dysfunction [17] [18] [19] [20]. The aim of this study was to develop a simple yeast model to study the biology of human Parkin. "
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    ABSTRACT: Mutations in Parkin, an E3 ubiquitin ligase, are associated to autosomal recessive Parkinson´s disease (PD). Parkin has been mainly implicated, along with Pink1, in mitochondrial autophagy in response to stress. In this study, a yeast model was developed to analyse the biological function of human Parkin. We observed that Parkin increases yeast chronological lifespan and oxidative stress resistance, through a mitochondrial-dependent pathway. Moreover, in response to H2O2, Parkin translocate to mitochondria, leading to a higher mitochondrial degradation. Parkin-induced H2O2 resistance is dependent on the autophagic pathway and on the mitochondrial protein Por1p. Although expression of Pink1 induces an H2O2 resistance phenotype similar to Parkin, co-expression of both proteins does not result in a synergistic effect. Concerning H2O2 resistance, this may indicate that these two proteins independently affect the same pathway. Altogether, this work establishes a yeast model for Parkin, which may provide new insights on Parkin function and potential mechanisms of pathogenicity. Copyright © 2015. Published by Elsevier Inc.
    Full-text · Article · Feb 2015 · Experimental Cell Research
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    • "Increasing evidence suggests that defects in vesicular trafficking are important for the pathogenic events leading to PD (Auluck, 2010; Lashuel et al., 2013; Waxman and Giasson, 2009). Several Rab GTPases were suggested to interact aberrantly with αS in Dementia with Lewy bodies (Soper et al., 2008, 2011; Sung et al., 2001). In addition, Rab proteins colocalize with glial inclusions containing αS in multiple system atrophy (Dalfo and Ferrer, 2005; Nakamura et al., 2000), Rab GTPases were found in vesicle clusters induced by αS overexpression in yeast (Gitler et al., 2008), and overexpression of the Rab GTPases Rab1, Rab3a and Rab8a decreased αS-induced neurotoxicity (Cooper et al., 2006; Gitler et al., 2008). "
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    ABSTRACT: Alpha-Synuclein (αS) misfolding is associated with Parkinson's disease (PD) but little is known about the mechanisms underlying αS toxicity. Increasing evidence suggests that defects in membrane transport play an important role in neuronal dysfunction. Here we demonstrate that the GTPase Rab8a interacts with αS in rodent brain. NMR spectroscopy reveals that the C-terminus of αS binds to the functionally important switch region as well as the C-terminal tail of Rab8a. In line with a direct Rab8a/αS interaction, Rab8a enhanced αS aggregation and reduced αS-induced cellular toxicity. In addition, Rab8 - the Drosophila ortholog of Rab8a - ameliorated αS-oligomer specific locomotor impairment and neuron loss in fruit flies. In support of the pathogenic relevance of the αS-Rab8a interaction, phosphorylation of αS at S129 enhanced binding to Rab8a, increased formation of insoluble αS aggregates and reduced cellular toxicity. Our study provides novel mechanistic insights into the interplay of the GTPase Rab8a and αS cytotoxicity, and underscores the therapeutic potential of targeting this interaction.
    Full-text · Article · Jun 2014 · Neurobiology of Disease
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    • "Many studies now implicate the Syn family generally, and α-Syn in particular, in both regulatory and pathological roles with regard to ER and Golgi function. While some of the relevant work has been conducted in neuronal culture systems or in vivo models, much of the data supporting involvement of the Syn proteins in the process of transmembrane protein trafficking comes from more generic mammalian cell culture models (eg NRK or COS-7 cells)24,25 or even yeast and other organisms that lack endogenous Syn protein expression.26,27 As these results continue to accumulate, it is important to relate the findings in these model systems to the admittedly more complex and less understood reality of transmembrane protein trafficking in actual neurons. "
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    ABSTRACT: More than 2 decades of work have yet to conclusively determine the physiological role of the synuclein proteins, even though these abundant brain constituents are participants in a broad array of cellular processes. Among proposed physiological roles is a functional interaction between the synuclein proteins and monoamine transporters contributing to transporter trafficking through direct protein-protein interactions. Recent work shows that an antagonistic effect of the synuclein proteins on the secretory functions of the endoplasmic reticulum and the Golgi apparatus appears to simultaneously influence trafficking of the dopamine transporter and other membrane proteins. Here, we highlight these new findings in view of the broader literature identifying the role of synucleins in protein trafficking and suggest emerging themes for ongoing and future work in the field of synuclein biology.
    Full-text · Article · Nov 2013 · Communicative & integrative biology
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