InterPro domain: IPR044776

The plant Polyol transporter (PLT) subfamily includes PLT1-6 from Arabidopsis thaliana and similar transporters [ 1 ]. The best characterised member of the group is Polyol transporter 5, also called Sugar-proton symporter PLT5, which mediates the H-symport of numerous substrates including linear polyols (such as sorbitol, xylitol, erythritol or glycerol), cyclic polyol myo-inositol, and different hexoses, pentoses (including ribose), tetroses, and sugar alcohols. It functions to transport a wide range of substrates into specific sink tissues in the plant [ 2 , 3 ]. The PLT subfamily belongs to the Glucose transporter-like (GLUT-like) family of the Major Facilitator Superfamily (MFS) of membrane transport proteins. MFS proteins are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement [ 4 ].

1. The monosaccharide transporter gene family in land plants is ancient and shows differential subfamily expression and expansion across lineages. BMC Evol Biol 6, 64
2. Arabidopsis POLYOL TRANSPORTER5, a new member of the monosaccharide transporter-like superfamily, mediates H+-Symport of numerous substrates, including myo-inositol, glycerol, and ribose. Plant Cell 17, 204-18
3. Analysis of transport activity of Arabidopsis sugar alcohol permease homolog AtPLT5. J Biol Chem 280, 1594-602
4. Structural advances for the major facilitator superfamily (MFS) transporters. Trends Biochem Sci 38, 151-9