This gene encodes the evolutionarily ancient and most conserved member of the cysteine proteases that plays important role in stress-induced apoptosis, DNA repair and tumor suppression. Mice lacking the encoded protein develop normally but display cell type-specific apoptotic defects. Germ cells and oocytes from such mice were found to be resistant to cell death after treatment with chemotherapeutic drugs. [provided by RefSeq, Apr 2015]