Proteolytic cleavage of vimentin during glucocorticoid-induced apoptosis

Previous work from our laboratory has demonstrated proteolytic cleavage of lamin Bl during glucocorticoid-induced thymocyte apoptosis. Lamin Bl shares homology with the intermediate filament vimentin. The following study was undertaken to investigate th e possible proteolytic cleavage of vimentin during apoptosis. Treatment of thymocytes with glucocorticoids resulted in a time-dependent proteolysis of vimentin and subsequent cellular shrinkage. Further investigation revealed the involvement of multiple proteases, such as ICE family members, calpains I and II, and the nuclear scaffold associated protease in vimentin degradation and cellular shrinkage. In conclusion, our results demonstrate vimentin cleavage in glucocorticoid treated thymocytes, an even t, that is mediated by various proteases associated with the apoptotic process.