Abstract

The bcl‐2 gene product, a 25 kDa membrane protein residing at mitochondrial, microsomal and nuclear membrane sites within many cell types, is a broad and potent inhibitor of cell death by apoptosis. A family of bcl‐2‐related genes with death‐inhibiting or ‐promoting activities has recently been described, indicating a potentially quite complex cell death regulatory network at the level of gene expression and protein‐protein interactions. The function of bcl‐2 may be to regulate a final common pathway in apoptosis. Current hypotheses suggest that oxidative stress, specific proteolytic activity or cell cycle control may be common elements in apoptosis through which bcl‐2 exerts its survival function. Based on the extent to which elements of apoptotic pathways overlap with non‐apoptotic cellular functions, the physiological role of bcl‐2 may also extend to other cellular processes such as differentiation and proliferation.