Protein Domain : Type IV pilus inner membrane component PilN IPR007813

Type	Family
Description	Bacterial type IV pili are surface filaments critical for diverse biological processes including surface and host cell adhesion, colonisation, biofilm formation, twitching motility, DNA uptake during natural transformation and virulence [ , ]. The proteins necessary to form the type IV pili inner-membrane complex, are included in the pilMNOPQ operon which encodes the cytoplasmic actin-like protein PilM, PilN, PilO, the periplasmic lipoprotein PilP and the outer-membrane secretin PilQ. The inner-membrane PilM/N/O/P complex is required for the optimal function of the outer-membrane secretin PilQ. This cluster is highly conserved across the type IV pilus-producing bacterial species, and all of these proteins have been shown to be essential for twitching motility [, ].PilN forms a stable heterodimer with PilO through interaction of their periplasmic domains, being essential for the assembly of a functional complex. PilN requires PilO for a proper folding and they depend on each other for their stability [ , , ]. PilN also interacts with PilM causing conformational changes that allow PilM monomerisation.This entry also includes Type II secretion system protein L. Type II secretion (T2S) and type IV pilus systems share evolutionary origins, being structurally and functionally related [ ]. DNA utilization protein HofN from E.coli is also included in this entry. It is involved in DNA uptake and DNA utilisation as a carbon and energy source, conferring competitive advantage. This protein is encoded by a gene homologue to com genes in Haemophilus influenzae, involved in pilus biogenesis, protein secretion, competence-transformation, and twitching motility [ ].
Short Name	PilN