Homologous Superfamily

MFS transporter superfamily (IPR036259)

Short name: MFS_trans_sf

Overlapping entries



Transporters can be grouped in two classes, primary and secondary carriers. The primary active transporters drive solute accumulation or extrusion by using ATP hydrolysis, photon absorption, electron flow, substrate decarboxylation or methyl transfer. If charged molecules are unidirectionally pumped as a consequence of the consumption of a primary cellular energy source, electron chemical potential results. This potential can than be used to drive the active transport of additional solutes via secondary carriers.

Among the different transporter the two largest families that occur ubiquitously in all classifications of organisms are the ATP-Binding Cassette (ABC) primary transporter superfamily (see PDOC00185) and the Major Facilitator Superfamily (MFS). The MFS transporters are single-polypeptide secondary carriers capable only of transporting small solutes in response to chemiosmotic ion gradients [PMID: 9529885, PMID: 9868370]. They function as uniporters, symporters or antiporters. In addition their solute specificity are also diverse. MFS proteins contain 12 transmembrane regions (with some variations).

The 3D-structure of human GLUT1, an archetype of the major facilitator superfamily has been solved [PMID: 1157130]. Helices 1-5, 8, 10-12 are arranged in a 9-member barrel-like manner, delimiting a hydrophilic central channel. Helix 7 is located in the centre of the channel suggesting a role in regulating transport of solutes through the channel.

This entry represents MFS transporter superfamily, characterized by twelve transmembrane helices. This superfamily includes, among others, the glycerol-3-phosphate transporter from Escherichia coli, which transports glycerol-3-phosphate into the cytoplasm and inorganic phosphate into the periplasm [PMID: 12893936], and the E. coli proton/sugar transporter lactose permease (LacY), which acts to couple lactose and H+ translocation [PMID: 12893935, PMID: 16525509].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.