Serine protease with enterotoxic and cytotoxic activity. Internalization into the host cell is required for the induction of cytopathic effects. However, the serine activity is not necessary for secretion and internalization into the host cell. Inhibition of cytotoxic activity by phenylmethylsulfonyl fluoride. The cleaved C-terminal fragment (autotransporter domain) is localized in the outer membrane. The signal peptide, cleaved at the inner membrane, guides the autotransporter protein to the periplasmic space. Then, insertion of the C-terminal translocator domain in the outer membrane forms a hydrophilic pore for the translocation of the passenger domain to the bacterial cell surface, with subsequent cleavage. Cleaved to release the mature protein from the outer membrane.