This family contains a diverse range of predicted transporter proteins. Including the DctM subunit of the bacterial and archaeal TRAP C4-dicarboxylate transport (Dct) system permease. In general, C4-dicarboxylate transport systems allow C4-dicarboxylates like succinate, fumarate, and malate to be taken up. TRAP C4-dicarboxylate carriers are secondary carriers that use an electrochemical H+ gradient as the driving force for transport. DctM is an integral membrane protein that is one of the constituents of TRAP carriers [1]. Note that many family members are hypothetical proteins.

1: C4-dicarboxylate carriers and sensors in bacteria. Janausch IG, Zientz E, Tran QH, Kroger A, Unden G; Biochim Biophys Acta 2002;1553:39-56. PMID:11803016