Monocarboxylate transporter 9 of the Major Facilitator Superfamily of transporters
Monocarboxylate transporter 9 (MCT9) is also called Solute carrier family 16 member 9 (SLC16A9). It is an orphan transporter that is expressed in a number of tissues including intestine and kidney. A missense variant of MCT9 (K258T) is associated with significant increase in susceptibility to renal overload (ROL) gout with intestinal urate underexcretion. This suggests that MCT9 may have a role in intestinal urate excretion; it is possible that it transports urate. MCT9 belongs to the Monocarboxylate transporter (MCT) 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.
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.",