title: Farnesylation of Ydj1 is required for in vivo interaction with Hsp90 client proteins.
abstract: Ydj1 of Saccharomyces cerevisiae is an abundant cytosolic Hsp40, or J-type, molecular chaperone. Ydj1 cooperates with Hsp70 of the Ssa family in the translocation of preproteins to the ER and mitochondria and in the maturation of Hsp90 client proteins. The substrate-binding domain of Ydj1 directly interacts with steroid receptors and is required for the activity of diverse Hsp90-dependent client proteins. However, the effect of Ydj1 alteration on client interaction was unknown. We analyzed the in vivo interaction of Ydj1 with the protein kinase Ste11 and the glucocorticoid receptor. Amino acid alterations in the proposed client-binding domain or zinc-binding domain had minor effects on the physical interaction of Ydj1 with both clients. However, alteration of the carboxy-terminal farnesylation signal disrupted the functional and physical interaction of Ydj1 and Hsp90 with both clients. Similar effects were observed upon deletion of RAM1, which encodes one of the subunits of yeast farnesyltransferase. Our results indicate that farnesylation is a major factor contributing to the specific requirement for Ydj1 in promoting proper regulation and activation of diverse Hsp90 clients.
authors.affiliation: Department of Microbiology, Molecular Biology and Biochemistry and the Center for Reproductive Biology, University of Idaho, Moscow, ID 83844-3052, USA.
authors.forename: Gary A
authors.initials: GA
authors.lastname: Flom
authors.forename: Marta
authors.initials: M
authors.lastname: Lemieszek
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Fortunato
authors.forename: Jill L
authors.initials: JL
authors.lastname: Johnson
mesh_terms: D000818:Animals; D017353:Gene Deletion; D050956:HSP40 Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D009154:Mutation; D054876:Prenylation; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014166:Transferases / Q000235:genetics / Q000378:metabolism
chemical_list: D050956:HSP40 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D021122:Protein Subunits; D011965:Receptors, Glucocorticoid; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C070319:YDJ1 protein, S cerevisiae; D014166:Transferases; C070038:RAM1 protein, S cerevisiae; D020930:MAP Kinase Kinase Kinases; C067018:Ste11 protein, S cerevisiae