FtsQ/DivIB bacterial division proteins (Pfam:PF03799) contain an N-terminal POTRA domain (for polypeptide-transport-associated domain). This is found in different types of proteins, usually associated with a transmembrane beta-barrel. FtsQ/DivIB may have chaperone-like roles, which has also been postulated for the POTRA domain in other contexts [1].

1: POTRA: a conserved domain in the FtsQ family and a class of beta-barrel outer membrane proteins. Sanchez-Pulido L, Devos D, Genevrois S, Vicente M, Valencia A; Trends Biochem Sci 2003;28:523-526. PMID:14559180