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Farnesylation of Ydj1 Is Required for In Vivo Interaction with Hsp90 Client Proteins

Authors :
Gary Flom
Jill L. Johnson
Marta Kinga Lemieszek
Elizabeth A. Fortunato
Source :
Molecular Biology of the Cell. 19:5249-5258
Publication Year :
2008
Publisher :
American Society for Cell Biology (ASCB), 2008.

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.

Details

ISSN :
19394586 and 10591524
Volume :
19
Database :
OpenAIRE
Journal :
Molecular Biology of the Cell
Accession number :
edsair.doi.dedup.....4a01887136872eb879a5bc02b706b324