This family contains the bacterial protein PilM (approximately 150 residues long). PilM is an inner membrane protein that has been predicted to function as a component of the pilin transport apparatus and thin-pilus basal body [1].

1: Genes required for plasmid R64 thin-pilus biogenesis: identification and localization of products of the pilK, pilM, pilO, pilP, pilR, and pilT genes. Sakai D, Komano T; J Bacteriol 2002;184:444-451. PMID:11751821