Core component of the type II secretion system required for the energy-dependent secretion of extracellular factors such as proteases and toxins from the periplasm (PubMed:15590656, PubMed:16078004). Pseudopilin (pilin-like) protein that polymerizes to form the pseudopilus (PubMed:11931643). Further polymerization triggers pseudopilus growth (PubMed:11931643). Type II secretion system is composed of four main components: the outer membrane complex, the inner membrane complex, the cytoplasmic secretion ATPase and the periplasm-spanning pseudopilus. Forms homomultimers (By similarity). Interacts with pseudopilin tip complex component XpsJ as well as XpsI and XcpH (PubMed:16078004). Interacts with XpsN and secretin XpsD (PubMed:15590656). Cleaved by the prepilin peptidase. Methylated by prepilin peptidase at the amino group of the N-terminal methionine once the leader sequence is cleaved. Deletion mutants can no longer assemble into the pillar-like structure. Belongs to the GSP G family.