Self-Destructing Inhibitors

Science's STKE  09 May 2000:
Vol. 2000, Issue 31, pp. tw6
DOI: 10.1126/stke.2000.31.tw6

Mammalian cells contain proteins that function as endogenous inhibitors of apoptosis (IAPs) and that act, at least in part, by inhibiting caspases, proteases that mediate signals leading to cell death. In thymocytes, inhibitors of the proteasome, a protein complex that mediates proteolysis of ubiquitin-tagged proteins, can block apoptosis. Yang et al. find that the IAPs have ubiquitin ligase activity and that they appear to catalyze auto-ubiquitination. This activity increases in response to apoptotic stimuli, indicating that regulated proteolysis of IAPs contributes to the control of cell death in thymocytes.

Yang, Y., Fang, S., Jensen, J.P., Weissman, A.M., and Ashwell, J.D. (2000) Ubiquitin protein ligase activity of IAPs and their degradation in proteasomes in response to apoptotic stimuli. Science 288: 874-877. [Abstract] [Full Text]