Although archaeal flagella appear superficially similar to those of bacteria, they are quite distinct[1]. In several archaea, the flagellin genes are followed immediately by the flagellar accessory genes flaCDEFGHIJ. The gene products may have a role in translocation, secretion, or assembly of the flagellum. FlaC is a protein whose exact role is unknown but it has been shown to be membrane-associated (by immuno-blotting fractionated cells) [2].

1: The archaeal flagellum: a different kind of prokaryotic motility structure. Thomas NA, Bardy SL, Jarrell KF; FEMS Microbiol Rev 2001;25:147-174. PMID:11250034

2: Characterization of flagellum gene families of methanogenic archaea and localization of novel flagellum accessory proteins. Thomas NA, Jarrell KF; J Bacteriol 2001;183:7154-7164. PMID:11717274