Calcium-regulated non-lysosomal thiol-protease which catalyzes limited proteolysis of substrates involved in cytoskeletal remodeling and signal transduction. This small subunit may act as a tissue-specific chaperone of the large subunit, possibly by helping it fold into its correct conformation for activity.
Subcellular locations: Cytoplasm, Cell membrane
Translocates to the plasma membrane upon calcium binding.