Porin. Induces apoptosis in human cells through caspases-dependent and AIF-dependent pathways. Purified Omp38 enters the cells and localizes to the mitochondria, which leads to a release of proapoptotic molecules such as cytochrome c and AIF (apoptosis-inducing factor). Homotrimer. Belongs to the outer membrane OOP (TC 1.B.6) superfamily.