Heat-shock proteins as death determinants

The molecular pathways that mediate apoptosis are tightly regulated by a se ries of positive and negative signals, the balance of which determines whet her or not cells commit suicide. New data from several laboratories now sho w that heat-shock proteins (HSPs) can influence this process through direct physical interaction with key components of the apoptotic machinery. These reports marry the survival (or death)-endowing properties of HSPs to the c ell-death pathway.