InterPro domain: IPR004316

This family contains specific sugar efflux transporters that are essential for the maintenance of animal blood glucose levels, plant nectar production, and plant seed and pollen development. In many organisms it mediates glucose transport; in Arabidopsis it is necessary for pollen viability; and two of the rice homologues are specifically exploited by bacterial pathogens for virulence by means of direct binding of a bacterial effector to the SWEET promoter [ 1 ]. Homologues of SWEETs have been identified in bacteria [ 2 ].

The founding member of the SWEET family, MtN3, was identified as a nodulin-specific EST in the legume Medicago truncatula [ 3 ]. Another protein in this family may be involved in activation and expression of recombination activation genes (RAGs) [ 4 ].

This family contains a region of two transmembrane helices that is found in two copies in most members of the family.

1. Sugar transporters for intercellular exchange and nutrition of pathogens. Nature 468, 527-32
2. Functional role of oligomerization for bacterial and plant SWEET sugar transporter family. Proc. Natl. Acad. Sci. U.S.A. 110, E3685-94
3. Use of a subtractive hybridization approach to identify new Medicago truncatula genes induced during root nodule development. Mol. Plant Microbe Interact. 9, 233-42
4. Molecular cloning and characterization of a novel stromal cell-derived cDNA encoding a protein that facilitates gene activation of recombination activating gene (RAG)-1 in human lymphoid progenitors. Biochem. Biophys. Res. Commun. 221, 744-9