Hsp72 and stress kinase c-jun N-terminal kinase regulate the Bid-dependent pathway in tumor necrosis factor-induced apoptosis

Vladimir L. Gabai, Katsuhide Mabuchi, Dick D. Mosser, Michael Y. Sherman

Research output: Contribution to journalArticlepeer-review

142 Scopus citations

Abstract

The major inducible heat shock protein Hsp72 has been shown to protect cells from certain apoptotic stimuli. Here we investigated the mechanism of Hsp72-mediated protection from tumor necrosis factor (TNF)-induced apoptosis of primary culture of IMR90 human fibroblasts. Hsp72 temporarily blocked apoptosis in response to TNF and permanently protected cells from heat shock. An Hsp72 mutant (Hsp72ΔEEVD) with a deletion of the four C-terminal amino acids, which are essential for the chaperone function, blocked TNF-induced apoptosis in a manner similar to that of normal Hsp72 but did not inhibit heat shock-induced death. Therefore, the chaperone activity of Hsp72 is dispensable for suppression of TNF-induced apoptosis but is required for protection from heat shock. In fibroblasts derived from Bid knockout mice, similar temporal inhibition of TNF-induced apoptosis was seen. In these cells neither normal Hsp72 nor Hsp72ΔEEVD conferred additional protection from apoptosis, suggesting that Hsp72 specifically affects Bid-dependent but not Bid-independent apoptotic pathways. Furthermore, both normal Hsp72 and ΔHsp72EEVD inhibited Bid activation and downstream events, including release of cytochrome c, activation of caspase 3, and cleavage of poly-ADP-ribose polymerase. Both Hsp72 and ΔHsp72EEVD blocked activation of the stress kinase c-jun N-terminal kinase (JNK) by TNF, and specific inhibition of JNK similarly temporarily blocked Bid activation and the downstream apoptotic events. These data strongly suggest that in TNF-induced apoptosis, Hsp72 specifically interferes with the Bid-dependent apoptotic pathway via inhibition of JNK.

Original languageEnglish
Pages (from-to)3415-3424
Number of pages10
JournalMolecular and Cellular Biology
Volume22
Issue number10
DOIs
StatePublished - 2002
Externally publishedYes

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