Acts as a cysteine protease in controlling programmed cell death (apoptosis) by proteolytically activating or inactivating a wide range of substrates. Component of the egl-1, ced-9, ced-4 and ced-3 apoptotic signaling cascade required for the initiation of programmed cell death in cells fated to die during embryonic and postembryonic development. During oogenesis, required for germline apoptosis downstream of ced-9 and ced-4 but independently of egl-1. By cleaving and activating ced-8, promotes phosphatidylserine exposure on the surface of apoptotic cells; phosphatidylserine is a specific marker only present at the surface of apoptotic cells and acts as a specific signal for engulfment. By cleaving and converting dcr-1 into a deoxyribonuclease (DNase), promotes apoptotic chromosomal DNA fragmentation. By cleaving mitochondrial fission protein drp-1, may regulate the removal of mitochondria during apoptosis. During germline apoptosis, cleaves translation initiation factor ifg-1 (isoform p170) promoting cap-independent translation. During male tail morphogenesis, promotes apoptosis of the tail-spike cell downstream of ced-4 but independently of egl-1 and ced-9. By cleaving cnt-1, prevents the activation of the prosurvival akt-1/2 signaling pathway and thus promotes apoptosis. Downstream of ced-4, may play a role in sex-specific cell apoptosis by cleaving sex-determining protein fem-1. May regulate germline apoptosis in response to DNA damage, probably downstream of let-60/ras and mpk-1 pathway. Cleaves ced-9 in vitro. Cleaves csp-2 isoform b resulting in the removal of the propeptide and the generation of csp-2 subunit p31 in vitro. Independently of its apoptotic role has additional functions. Probably by cleaving and thereby activating actin-severing protein gsnl-1, required for the elimination of transient presynaptic components during larval development downstream of egl-1, ced-9 and ced-4 pathway. Together with ain-1, a component of the miRNA-induced-silencing complex (miRISC), regulates temporal cell fate patterning during larval development. In complex with ubr-1, which is E3 ubiquitin-protein ligase and component of the N-end rule pathway, acts in seam cell fate patterning during larval development by cleaving the heterochronic protein lin-28, and promoting its degradation. Also cleaves heterochronic protein lin-14 and exonuclease disl-2 in vitro. Downstream of calreticulin crt-1 and ced-4 and independently of egl-1 and ced-9, plays a role in the initial steps of axonal regrowth following axotomy. Cleaves 14-3-3-like protein ftt-2, tubulin tbb-2 and calreticulin crt-1 in vitro. Plays also a role in resistance to S.typhimurium-mediated infection.
