Major component of the type IV pilus (T4P) that plays a role in surface and host cell adhesion, colonization, biofilm maturation, virulence, and twitching, a form of surface-associated motility facilitated by cycles of extension, adhesion, and retraction of T4P fibers (PubMed:9282737, PubMed:26041805, PubMed:31431558). In addition, plays a critical role in type II secretion of exoenzymes by interacting with specific components such as XcpT or XcpU (PubMed:9282737). Modulates host calcium signaling through interaction with host calcium-modulating cyclophilin ligand (PubMed:23266901). Interacts with PilJ (PubMed:26041805). Interacts with PilS at the inner membrane (PubMed:27162347). Interacts with type II secretion system (T2SS) components XcpT, XcpU and XcpW (PubMed:9282737). Methylated by prepilin peptidase PilD at the amino group of the N-terminal phenylalanine once the leader sequence is cleaved. Mutants show a significant reduction in the efficiency of extracellular protein secretion (PubMed:9282737). They are also defective in twitching motility (PubMed:31431558). Belongs to the N-Me-Phe pilin family.