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JNK phosphorylates the HSF1 transcriptional activation domain: Role of JNK in the regulation of the heat shock response
Author(s) -
Park Jeonghyeon,
Liu Alice Y.C.
Publication year - 2001
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.1163
Subject(s) - hsf1 , anisomycin , mg132 , heat shock , phosphorylation , microbiology and biotechnology , heat shock protein , hsp70 , heat shock factor , activator (genetics) , kinase , chemistry , biology , proteasome inhibitor , proteasome , biochemistry , gene
The role of c‐Jun NH 2 ‐terminal kinase (JNK) signaling cascade in the stress‐inducible phosphorylation of heat shock factor 1 (HSF1) was investigated using known agonists and antagonists of JNK. We showed that treatment of HeLa cells with MG132, a proteasome inhibitor and known JNK activator, caused the transcriptional activation domain of HSF1 to be targeted and phosphorylated by JNK2 in vivo. Dose‐response and time course studies of the effects of heat shock and anisomycin treatment showed a close correlation of the activation of JNK and hyperphosphorylation of HSF1. SB203580 inhibited JNK at the 100 μM concentration and significantly reduced the amount of hyperphosphorylated HSF1 upon heat shock or anisomycin treatment. SB203580 and dominant‐negative JNK suppress hsp70 promoter‐driven reporter gene expression selectively at 45°C but not at 42°C heat stress, suggesting that JNK would be preferentially associated with the protective heat shock response against severe heat stress. The possibility that JNK‐mediated phosphorylation of HSF1 may selectively stabilize the HSF1 protein and confers protection to cells under conditions of severe stress is discussed. J. Cell. Biochem. 82: 326–338, 2001. © 2001 Wiley‐Liss, Inc.