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c-Jun NH2-terminal kinase targeting and phosphorylation of heat shock factor-1 suppress its transcriptional activity.

Authors
Dai-RJ; Frejtag-W; He-B; Zhang-Y; Mivechi-NF
Source
J Biol Chem 2000 Jun; 275(24):18210-18218
NIOSHTIC No.
20032670
Abstract
The mammalian heat shock transcription factor HSF-1 regulates the expression of the heat shock proteins, molecular chaperones that are involved in cellular processes from higher order assembly to protein degradation. HSF-1 is a phosphorylated monomer under physiological growth conditions and is located mainly in the cytoplasm. Upon activation by a variety of environmental stresses, HSF-I is translocated into the nucleus, forms trimers, acquires DNA binding activity, is hyperphosphorylated, appears as punctate granules, and increases transcriptional activity of target genes. As cells recover from stress, the punctate granules gradually disappear, and HSF-I appears in a diffused staining pattern in the cytoplasm and nucleus. We have previously shown that the mitogen-activated protein kinase ERK phosphorylates and suppresses HSF-l-driven transcription. Here, Re show that c-Jun NH2-terminal kinase (JNK) also phosphorylates and inactivates HSF-I. Overexpression of JNK facilitates the rapid disappearance of HSF-1 punctate granules after heat shock Similar to ERE, JNK binds to HSF-1 in the conserved mitogen-activated protein kinases binding motifs and phosphorylates HSF-1 in the regulatory domain. The overexpression of an HSF-l-green fluorescent protein fusion construct lacking JNK phosphorylation sites causes this HSF-1 mutant to form nuclear granules that remain longer in the nucleus after heat shock. Taken together, these findings indicate that JNK phosphorylates HSF-1 and suppresses its transcriptional activity by rapidly clearing HSF-1 hom the sites of transcription.
Keywords
Heat; Heat-exchange; Heat-stress; Cell-biology; Cell-differentiation; Cell-function; Cell-metabolism; Cellular-transport-mechanism; Analytical-methods; Analytical-processes; Physiology; Physiological-function; Physiological-response; Physiological-stress; Genes; Genetic-factors; Molecular-biology; Environmental-exposure; Environmental-factors; Environmental-hazards
Contact
NF Mivechi, Institute of Molecular Medicine and Genetics, Gene Regulation Group, and Dept. of Radiology, Medical College of Georgia, 1120 15th St., CB2803, Augusta, GA 30912
CODEN
JBCHA3
Publication Date
20000616
Document Type
Journal Article
Email Address
mivechi@immag.mcg.edu
Fiscal Year
2000
NTIS Accession No.
NTIS Price
Issue of Publication
24
ISSN
0021-9258
NIOSH Division
OD
Source Name
Journal of Biological Chemistry
State
WV; GA
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