Caspase-10-Mediated Heat Shock Protein 90β Cleavage Promotes UVB Irradiation-Induced Cell Apoptosis

Abstract

ABSTRACT Heat shock protein 90β (Hsp90β) is involved in many cellular functions. However, the posttranslational modification of Hsp90β, especially in response to apoptotic stimulation, is not well understood. In this study, we found that Hsp90β was cleaved by activated caspase-10 under UVB irradiation. Caspase-10 activation, in turn, depended on caspase-8, which cleaved caspase-10 directly. Autocrine secretion of FAS ligand and upregulated FAS expression induced by UVB irradiation contributed to activation of caspase-10, which cleaved Hsp90β at D278, P293, and D294. The downregulation of Hsp90β mediated by caspase-8-dependent caspase-10 activation promoted UVB-induced cell apoptosis.