Prion-specific Hsp40 function: The role of the auxilin homolog Swa2.
Yeast prions are protein-based genetic elements that propagate through cell populations via cytosolic transfer from mother to daughter cell. Molecular chaperone proteins including Hsp70, the Hsp40/J-protein Sis1, and Hsp104 are required for continued prion propagation, however the specific requirements of chaperone proteins differ for various prions. We recently reported that Swa2, the yeast homolog of the mammalian protein auxilin, is specifically required for the propagation of the prion [URE3]. 1 [URE3] propagation requires both a functional J-domain and the tetratricopeptide repeat (TPR) domain of Swa2, but does not require Swa2 clathrin binding. We concluded that the TPR domain determines the specificity of the genetic interaction between Swa2 and [URE3], and that this domain likely interacts with one or more proteins with a C-terminal EEVD motif. Here we extend that analysis to incorporate additional data that supports this hypothesis. We also present new data eliminating Hsp104 as the relevant Swa2 binding partner and discuss our findings in the context of other recent work involving Hsp90. Based on these findings, we propose a new model for Swa2's involvement in [URE3] propagation in which Swa2 and Hsp90 mediate the formation of a multi-protein complex that increases the number of sites available for Hsp104 disaggregation.
['Oliver|Emily E|EE|', 'Troisi|Elizabeth M|EM|', 'Hines|Justin K|JK|']
D034021:Auxilins D005979:Glutathione Peroxidase D050956:HSP40 Heat-Shock Proteins D018841:HSP90 Heat-Shock Proteins D006360:Heat-Shock Proteins D010750:Phosphoproteins D011328:Prions D011485:Protein Binding D012441:Saccharomyces cerevisiae D029701:Saccharomyces cerevisiae Proteins D033921:Vesicular Transport Proteins
Ssa Sup35 amyloid cell stress heat-shock neurodegenerative protein folding protein misfolding ure2