The Sch9 protein kinase regulates Hsp90 chaperone complex signal transduction activity in vivo.


Journal Article

Basal and stress-induced synthesis of the components of the highly conserved heat shock protein Hsp90 chaperone complex require the heat shock transcription factor (HSF); Saccharomyces cerevisiae cells expressing the HSF allele HSF(1-583) reversibly arrest growth at 37 degrees C in the G(2)/M phase of the cell cycle due to diminished expression of these components. A suppressor mutant capable of restoring high-temperature growth to HSF(1-583) cells was identified, harboring a disruption of the SCH9 protein kinase gene, homologous to the protein kinase A and protein kinase B/Akt families of mammalian growth control kinases. Loss of Sch9 in HSF(1-583) cells derepresses Hsp90 signal transduction functions as demonstrated by restoration of transcriptional activity by the mammalian glucocorticoid receptor and the heme-dependent transcription factor Hap1, and by enhanced pheromone-dependent signaling through the Ste11 mitogen-activated protein kinase (MAPK). Moreover, Sch9-deficient cells with normal levels of Hsp90 chaperone complex components display hyperactivation of the pheromone response MAPK pathway in the absence of pheromone. These results demonstrate that the evolutionarily conserved function of the Hsp90 chaperone complex as a signal transduction facilitator is modulated by a growth regulatory kinase.

Full Text

Duke Authors

Cited Authors

  • Morano, KA; Thiele, DJ

Published Date

  • November 1, 1999

Published In

Volume / Issue

  • 18 / 21

Start / End Page

  • 5953 - 5962

PubMed ID

  • 10545107

Pubmed Central ID

  • 10545107

International Standard Serial Number (ISSN)

  • 0261-4189

Digital Object Identifier (DOI)

  • 10.1093/emboj/18.21.5953


  • eng

Conference Location

  • England