Solute carrier 46 (SLC46) family of the Major Facilitator Superfamily of transporters
The solute carrier 46 (SLC46) family is composed of three vertebrate members (SLC46A1, SLC46A2, and SLC46A3) and similar proteins from insects and nematodes. The best-studied member is SLC46A1, also called proton-coupled folate transporter (PCFT), which functions both as an intestinal proton-coupled high-affinity folate transporter involved in the absorption of folates and as an intestinal heme transporter which mediates heme uptake. SLC46A2, also called thymic stromal cotransporter protein (TSCOT), is a putative 12-transmembrane protein mainly expressed in the thymic cortex in a specific thymic epithelial cell (TEC) subpopulation. SLC46A3 is a lysosomal membrane protein that functions as a direct transporter of noncleavable antibody maytansine-based catabolites from the lysosome to the cytoplasm. The SLC46 family belongs to the Eukaryotic Solute carrier 46 (SLC46)/Bacterial Tetracycline resistance (TetA) -like (SLC46/TetA-like) family of the Major Facilitator Superfamily (MFS) of transporters. MFS proteins are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement.
Feature 1:putative chemical substrate binding pocket [chemical binding site]
Evidence:
Comment:based on the structures of MFS transporters with bound substrates, substrate analogs, and/or inhibitors
Comment:since MFS proteins facilitate the transport of many different substrates including ions, sugar phosphates, drugs, neurotransmitters, nucleosides, amino acids, and peptides, the residues involved in substrate binding may not be strictly conserved among superfamily members
Comment:the substrate binding site or translocation pore has access to both sides of the membrane in an alternating fashion through a conformational change of the MFS transporter
Jiyao W et al.(2023). "The conserved domain database in 2023.",