Solute carrier family 37 members 1 (SLC37A1) and 2 (SLC37A2) are also called sugar phosphate exchangers 1 (SPX1) and 2 (SPX2). SLC37A1 and SLC37A2 are ER-associated, Pi-linked antiporters that can transport glucose-6-phosphate (G6P) but are insensitive to chlorogenic acid, a competitive inhibitor of physiological ER G6P transport, unlike SLC37A4, the best characterized SLC37 family member and is the physiological G6P transporter (G6PT) []. SLC37A1 and SLC37A2 belong to the Organophosphate:Pi antiporter (OPA)/SLC37 family, whose members are integral membrane proteins responsible for the transport of specific organophosphates or sugar phosphates across biological membranes with the simultaneous translocation of inorganic phosphate into the opposite direction [].The OPA/SLC37 family belongs to the Major Facilitator Superfamily (MFS) of membrane transport proteins, which are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement [].
