Mammalian ribosomal and chaperone protein RPS3A counteracts α-synuclein aggregation and toxicity in a yeast model system.
Accumulation of aggregated forms of αSyn (α-synuclein) into Lewy bodies is a known hallmark associated with neuronal cell death in Parkinson's disease. When expressed in the yeast Saccharomyces cerevisiae, αSyn interacts with the plasma membrane, forms inclusions and causes a concentration-dependent growth defect. We have used a yeast mutant, cog6Δ, which is particularly sensitive to moderate αSyn expression, for screening a mouse brain-specific cDNA library in order to identify mammalian proteins that counteract αSyn toxicity. The mouse ribosomal and chaperone protein RPS3A was identified as a suppressor of αSyn [WT (wild-type) and A53T] toxicity in yeast. We demonstrated that the 50 N-terminal amino acids are essential for this function. The yeast homologues of RPS3A were not effective in suppressing the αSyn-induced growth defect, illustrating the potential of our screening system to identify modifiers that would be missed using yeast gene overexpression as the first screening step. Co-expression of mouse RPS3A delayed the formation of αSyn-GFP inclusions in the yeast cells. The results of the present study suggest that the recently identified extraribosomal chaperonin function of RPS3A also acts on the neurodegeneration-related protein αSyn and reveal a new avenue for identifying promising candidate mammalian proteins involved in αSyn functioning.
‡Biochemistry, Molecular and Structural Biology section, KU Leuven, Celestijnenlaan 200G, B-3001 Leuven-Heverlee, Flanders, Belgium.
Stijn
S
De Graeve
Sarah
S
Marinelli
Frank
F
Stolz
Jelle
J
Hendrix
Jurgen
J
Vandamme
Yves
Y
Engelborghs
Patrick
P
Van Dijck
Johan M
JM
Thevelein
D000818:Animals; D008322:Mammals; D051379:Mice; D018832:Molecular Chaperones / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D051844:alpha-Synuclein / Q000378:metabolism*
D018832:Molecular Chaperones; C501334:RPS3 protein, S cerevisiae; D012269:Ribosomal Proteins; C488930:Rsp3a1 protein, mouse; D029701:Saccharomyces cerevisiae Proteins; D051844:alpha-Synuclein