Plays a major role in programmed cell death (PCD, apoptosis). egl-1 binds to and directly inhibits the activity of ced-9, releasing the cell death activator ced-4 from a ced-9/ced-4 containing protein complex and allowing ced-4 to activate the cell-killing caspase ced-3. During larval development, required for the elimination of transient presynaptic components downstream of egl-1 and upstream of ced-4 and ced-3 apoptotic pathway. Interacts with asymmetric homodimer ced-4; the interaction sequesters ced-4. Interacts with egl-1; the interaction results in ced-4 release. Interacts with dre-1; the interaction inhibits ced-9 activity, either directly or indirectly. Interacts with dct-1. May form a complex composed of ced-9, ced-4 and mac-1. Intracellular membranes, mitochondrial, and perinuclear region. Localizes to synapses of DD motor neurons. Synaptic localization is dependent on axonal mitochondria. Belongs to the Bcl-2 family. Extended N-terminus.