Requirements of Hsp104p activity and Sis1p binding for propagation of the [RNQ+] prion

摘要: The formation and maintenance of prions in the yeast Saccharomyces cerevisiae is highly regulated by cellular chaperone machinery. most important player this regulation Hsp104p, which required for all known prions. requirements other chaperones, such as members Hsp40 or Hsp70 families, vary with each individual prion. [RNQ(+)] cells do not have a phenotype that amenable to genetic screens identify factors prion propagation. Therefore, we used chimeric construct reports status perform screen mutants are unable maintain [RNQ(+)]. We found eight separate mutations Hsp104p caused become [rnq(-)]. These also loss [PSI(+)] expression one these mutants, Hsp104p-E190K, showed differential presence wild type Hsp104p. Hsp104p-E190K inefficiently propagated was [PSI(+)]. mutant act on vivo substrates, strains carrying it were thermotolerant. Purified recombinant reduced level ATP hydrolysis compared protein. This likely cause both lack function. Furthermore, suggests requires less activity transmissible protein aggregates than Sup35p. Additionally, show L94A mutation Rnq1p, reduces its interaction Sis1p, prevents Rnq1p from maintaining inducing