Mutations in the Yeast Hsp70, Ssa1, at P417 Alter ATP Cycling, Interdomain Coupling, and Specific Chaperone Functions.

ABSTRACT: The major cytoplasmic Hsp70 chaperones in the yeast Saccharomyces cerevisiae are the Ssa proteins, and much of our understanding of Hsp70 biology has emerged from studying ssa mutant strains. For example, Ssa1 catalyzes multiple cellular functions, including protein transport and degradation, and to this end, the ssa1-45 mutant has proved invaluable. However, the biochemical defects associated with the corresponding Ssa1-45 protein (P417L) are unknown. Consequently, we characterized Ssa1 P417L, as well as a P417S variant, which corresponds to a mutation in the gene encoding the yeast mitochondrial Hsp70. We discovered that the P417L and P417S proteins exhibit accelerated ATPase activity that was similar to the Hsp40-stimulated rate of ATP hydrolysis of wild-type Ssa1. We also found that th

SUBMITTER: Needham PG 

PROVIDER: S-EPMC4569534 | biostudies-literature | 2015 Sep

REPOSITORIES: biostudies-literature