title: Suppression of α-synuclein toxicity and vesicle trafficking defects by phosphorylation at S129 in yeast depends on genetic context.
abstract: The aggregation of α-synuclein (αSyn) is a neuropathologic hallmark of Parkinson's disease and other synucleinopathies. In Lewy bodies, αSyn is extensively phosphorylated, predominantly at serine 129 (S129). Recent studies in yeast have shown that, at toxic levels, αSyn disrupts Rab homeostasis, causing an initial endoplasmic reticulum-to-Golgi block that precedes a generalized trafficking collapse. However, whether αSyn phosphorylation modulates trafficking defects has not been evaluated. Here, we show that constitutive expression of αSyn in yeast impairs late-exocytic, early-endocytic and/or recycling trafficking. Although members of the casein kinase I (CKI) family phosphorylate αSyn at S129, they attenuate αSyn toxicity and trafficking defects by an S129 phosphorylation-independent mechanism. Surprisingly, phosphorylation of S129 modulates αSyn toxicity and trafficking defects in a manner strictly determined by genetic background. Abnormal endosome morphology, increased levels of the endosome marker Rab5 and co-localization of mammalian CKI with αSyn aggregates are observed in brain sections from αSyn-overexpressing mice and human synucleinopathies. Our results contribute to evidence that suggests αSyn-induced defects in endocytosis, exocytosis and/or recycling of vesicles involved in these cellular processes might contribute to the pathogenesis of synucleinopathies.
authors.affiliation: Gladstone Institute of Neurological Disease, 1650 Owens Street, San Francisco, CA 94158, USA.
authors.forename: Vicente
authors.initials: V
authors.lastname: Sancenon
authors.forename: Sue-Ann
authors.initials: SA
authors.lastname: Lee
authors.forename: Christina
authors.initials: C
authors.lastname: Patrick
authors.forename: Janice
authors.initials: J
authors.lastname: Griffith
authors.forename: Amy
authors.initials: A
authors.lastname: Paulino
authors.forename: Tiago F
authors.initials: TF
authors.lastname: Outeiro
authors.forename: Fulvio
authors.initials: F
authors.lastname: Reggiori
authors.forename: Eliezer
authors.initials: E
authors.lastname: Masliah
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Muchowski
mesh_terms: D000818:Animals; D047389:Casein Kinase I / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000378:metabolism; D010766:Phosphorylation; D021381:Protein Transport; D015003:Yeasts / Q000378:metabolism*; D051844:alpha-Synuclein / Q000235:genetics* / Q000378:metabolism
chemical_list: D051844:alpha-Synuclein; D047389:Casein Kinase I