This family contains several bacterial flagellar FliT proteins. The flagellar proteins FlgN and FliT have been proposed to act as substrate specific export chaperones, facilitating incorporation of the enterobacterial hook-associated axial proteins (HAPs) FlgK/FlgL and FliD into the growing flagellum. In Salmonella typhimurium flgN and fliT mutants, the export of target HAPs is reduced, concomitant with loss of unincorporated flagellin into the surrounding medium [1].

1: Substrate complexes and domain organization of the Salmonella flagellar export chaperones FlgN and FliT. Bennett JC, Thomas J, Fraser GM, Hughes C; Mol Microbiol 2001;39:781-791. PMID:11169117