BCL-2-FAMILY PROTEINS - THE ROLE OF THE BH3 DOMAIN IN APOPTOSIS

Bcl-2-related proteins have come to occupy a prominent position in the realm of programmed cell death. Members of this fast-growing family a re highly related in one or more specific regions, commonly referred t o as Bcl-2 homology (BH) domains. BH domains contribute at multiple le vels to the function of these proteins in cell death and survival. Par ticularly intriguing is the emergence of the BH3 domain as a potent 'd eath domain' and of a growing subclass of pro-apoptotic proteins with no similarity to Bcl-2 beyond their BH3 homology. Here, the authors cl assify, proteins of the Bcl-2 family on the basis of function and doma in organization, discuss the importance of the BH3 domain in protein-p rotein interactions and in cell death and provide possible explanation s for the perceived redundancy in the expression of this subclass of d eath promoters.