We have been focusing our approach on studying how alterations in primary structure of prion proteins can affect chaperone interactions. We have been isolating mutants of prion proteins that fall into two major classes, those that interfere with propagation of prions formed of wild type proteins and those that don't. Both types of mutants contain subclasses that, in the absence of wild type protein, either form prions with weakened phenotypes or are unable to form prions. We are using genetic and biochemical methods to determine if the observed effects on prion phenotpye are due to differences in how the prion proteins self-associate or interact with various chaperones. We are also isolating mutations in the Ure2 pion protein (the prion determinant of the URE3 prion) to identify alterations that specifically interfere with the ability of the Hsp40 chaperone Ydj1 to cure cells of URE3. Our preliminary work suggests that the prion protein mutations can influence propagation of amyloid or the interaction of chaperones that in turn affect how efficiently the prions propagate.

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Xue, You-Lin; Wang, Hao; Riedy, Michael et al. (2018) Molecular dynamics simulations of Hsp40 J-domain mutants identifies disruption of the critical HPD-motif as the key factor for impaired curing in vivo of the yeast prion [URE3]. J Biomol Struct Dyn 36:1764-1775
Zhao, Xiaohong; Lanz, Jenna; Steinberg, Danielle et al. (2018) Real-time imaging of yeast cells reveals several distinct mechanisms of curing of the [URE3] prion. J Biol Chem 293:3104-3117
Gorkovskiy, Anton; Reidy, Michael; Masison, Daniel C et al. (2017) Hsp104 disaggregase at normal levels cures many [PSI(+)] prion variants in a process promoted by Sti1p, Hsp90, and Sis1p. Proc Natl Acad Sci U S A 114:E4193-E4202
Reidy, Michael; Sharma, Ruchika; Roberts, Brittany-Lee et al. (2016) Human J-protein DnaJB6b Cures a Subset of Saccharomyces cerevisiae Prions and Selectively Blocks Assembly of Structurally Related Amyloids. J Biol Chem 291:4035-47
Zhao, Xiaohong; Park, Yang-Nim; Todor, Horia et al. (2012) Sequestration of Sup35 by aggregates of huntingtin fragments causes toxicity of [PSI+] yeast. J Biol Chem 287:23346-55