Component of the type II secretion system required for the energy-dependent secretion of extracellular factors such as proteases and toxins from the periplasm. Part of 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 GspG (By similarity). Interacts with pseudopilins GspJ and GspK (PubMed:18438417). Cleaved by prepilin peptidase. Methylated by prepilin peptidase at the amino group of the N-terminal phenylalanine once the leader sequence is cleaved by prepilin peptidase. Belongs to the GSP I family.