Calcium-regulated non-lysosomal thiol-protease which catalyzes limited proteolysis of substrates (By similarity). Required for assembly and maintenance of integrin attachment complexes which are essential for maintenance of adult muscle (PubMed:22253611). Proteolytic activity is activated in response to increased intracellular Ca(2+) levels during cell degeneration and promotes necrotic cell death (PubMed:12410314, PubMed:22479198). In body wall muscle cells, localizes at M-lines extending over the H-zone, and at adhesion plaques which form between adjacent cells. Experimental confirmation may be lacking for some isoforms. Expressed in muscle and neuronal tissues (PubMed:12410314, PubMed:22479198). Expressed in the ventral and dorsal nerve cord, intestinal and hypodermal tissues (PubMed:22479198). RNAi-mediated knockdown results in adult muscle defects which include irregularities in sarcomeric structures, disorganized integrin attachment complexes, and increased mitochondrial fragmentation (PubMed:22253611). RNAi-mediated knockdown in integrin attachment complex component mutants unc-112 (e669su250) and unc-52 (r367) blocks the protein degradation which normally results from complex disruption (PubMed:22253611). RNAi-mediated knockdown suppresses cell death in the neurodegenerative models deg-3 (u662), gsa-1 (Q227L) and mec-4 (u231) (PubMed:12410314). Belongs to the peptidase C2 family.