SELECTIVE ACTIVATION OF JNK1 IS NECESSARY FOR THE ANTI-APOPTOTIC ACTIVITY OF HILP

The balance between the inductive signals and endogenous anti-apoptoti c mechanisms determines whether or not programmed cell death occurs. T he widely expressed inhibitor of apoptosis gene family includes three closely related mammalian proteins: c-IAP1, c-IAP2, and hILP. The anti -apoptotic properties of these proteins have been linked to caspase in hibition. Here we show that one member of this group, hILP, inhibits i nterleukin-1 beta-converting enzyme-induced apoptosis via a mechanism dependent on the selective activation of c-Jun N-terminal kinase 1. Th ese data demonstrate that apoptosis tan be inhibited by an endogenous cellular protein by a mechanism that requires the activation of a sing le member of the mitogen-activating protein kinase family.