This family consists of proteins which form type IV pili. In M. xanthus these pili are required for social motility [1,2].

1: Genetic and functional evidence that Type IV pili are required for social gliding motility in Myxococcus xanthus. Wu SS, Kaiser D; Mol Microbiol. 1995;18:547-558. PMID:8748037

2: Regulating pilin expression reveals a threshold for S motility in Myxococcus xanthus. Jelsbak L, Kaiser D; J Bacteriol. 2005;187:2105-2112. PMID:15743959