Heat shock proteins: Endogenous modulators of apoptotic cell death

The highly conserved heat shock proteins (HSPs) accumulate in cells exposed to heat and a variety of other stressful stimuli. HSPs, which function mai nly as molecular chaperones, allow cells to adapt to gradual changes in the ir environment and to survive in otherwise lethal conditions. The events of cell stress and cell death are linked and HSPs induced in response to stre ss appear to function at key regulatory points in the control of apoptosis. HSPs include anti-apoptotic and proapoptotic proteins that interact with a variety of cellular proteins. Their expression level can determine the fat e of the cell in response to a death stimulus, and apoptosis-inhibitory HSP s, in particular HSP27 and HSP70, may participate in carcinogenesis. This r eview summarizes apoptosis-regulatory function of HSPs. (C) 2001 Academic P ress.