Initiates apoptosis in a BH3-independent mechanism possibly by recruiting ced-3 to mitochondria and other cytoplasmic membranes. Has a role in lifespan and tumor growth (By similarity). Homodimer; via transmembrane domain. Interacts with ced-3 and ced-9 (By similarity). Ubiquitinated and degraded by the proteasome. Belongs to the NIP3 family.