Component of the type II secretion system required for the energy-dependent secretion of extracellular factors such as proteases and toxins from the periplasm. Plays a role in pseudopilus assembly and seems to control its length. Interacts with the pseudopilus tip complex that is critical for the recognition and binding of secretion substrates. Type II secretion is composed of four main components: the outer membrane complex, the inner membrane complex, the cytoplasmic secretion ATPase and the periplasm-spanning pseudopilus. Interacts with core component OutG. Cleaved by prepilin peptidase. Belongs to the GSP K family.