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ATPase activity of the heat shock protein Hsp72 is dispensable for its effects on dephosphorylation of stress kinase JNK and on heat‐induced apoptosis
Author(s) -
Volloch Vladimir,
Gabai Vladimir L.,
Rits Sophia,
Sherman Michael Y.
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)01428-3
Subject(s) - dephosphorylation , heat shock protein , apoptosis , microbiology and biotechnology , kinase , mutant , phosphorylation , protein kinase a , atpase , biology , chemistry , biochemistry , enzyme , phosphatase , gene
A major inducible heat shock protein, Hsp72, has previously been found to stimulate dephosphorylation (inactivation) of stress kinase JNK in heat‐shocked cells and protect them from apoptosis. Using Rat‐1 fibroblasts with constitutive expression of a human Hsp72 or its deletion mutant lacking an ATPase domain (C‐terminal fragment (CTF)), we tested whether ATPase activity of Hsp72 is necessary for these effects. We found that expression of CTF markedly increased, similarly to the intact protein, JNK dephosphorylation in heat‐shocked cells. As a result, JNK inactivation following heat shock occurred much faster in cells expressing either full‐length or mutant Hsp72 than in parental cells and this was accompanied by suppression of heat‐induced apoptosis. Thus, protein refolding activity of Hsp72 appears to be dispensable for its effect on JNK inactivation and apoptosis.