Probable serine protease that plays a role in hearing. Acts as a permissive factor for cochlear hair cell survival and activation at the onset of hearing and is required for saccular hair cell survival (By similarity). Activates ENaC (in vitro).
Subcellular locations: Endoplasmic reticulum membrane
Expressed in many tissues including fetal cochlea. Isoform T is found at increased levels in some carcinomas.