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Upregulation of the Hsp104 chaperone at physiological temperature during recovery from thermal insult
Author(s) -
Seppä Laura,
Hänninen AnnaLiisa,
Makarow Marja
Publication year - 2004
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2003.03959.x
Subject(s) - downregulation and upregulation , biology , heat shock protein , chaperone (clinical) , saccharomyces cerevisiae , microbiology and biotechnology , transcription factor , heat shock factor , gene , hsp70 , gene expression , transcription (linguistics) , heat shock , biochemistry , philosophy , pathology , medicine , linguistics
Summary Thermal insult at 50°C causes protein denaturation in yeast, but the cells survive if preconditioned at 37°C. Survival depends on refolding of heat‐denatured proteins. Refolding of cytoplasmic proteins requires Hsp104, the expression of which increases several‐fold upon shift of the cells from physiological temperature 24°C to 37°C. We describe here a novel type of regulation of Hsp104, designated delayed upregulation (DUR). When Saccharomyces cerevisiae cells grown at 24°C, preconditioned at 37°C and treated briefly at 50°C were shifted back to 24°C, Hsp104 expression was negligible for 1 h, but increased then to a three to nine times higher level than that detected after growth at 24°C, returning to normal after 5 h. A heat shock element (HSE) of the upstream sequence of HSP104 was necessary and sufficient for DUR, whereas stress response elements (STRE) were dispensable. Destruction of HSE plus all three STREs abolished Hsp104 expression, resulting in cell death after thermal insult. Deletion of MSN2/4 , encoding transcription factors driving STRE‐dependent gene expression, decreased DUR. Deletion of HOG1 , encoding a heat‐responsive and osmosensitive mitogen‐activated protein kinase implicated to be functionally connected to Msn2/4p, abolished DUR. We suggest that DUR was regulated via HSE, required Hog1p and involved Msn2/4p‐regulated gene products.