SLC22A2
Description
The SLC22A2 (solute carrier family 22 member 2) is a protein-coding gene located on chromosome 6.
Solute carrier family 22 member 2 (SLC22A2), also known as OCT2 or organic cation transporter-2, is a protein encoded by the SLC22A2 gene in humans. Poly specific organic cation transporters in the liver, kidney, intestine, and other organs play a crucial role in eliminating many endogenous small organic cations, as well as a wide range of drugs and environmental toxins. The SLC22A2 gene is one of three similar cation transporter genes located in a cluster on chromosome 6. The encoded protein contains twelve putative transmembrane domains and is an integral membrane protein found primarily in the kidney. It may mediate the first step in cation reabsorption.
SLC22A2, also known as OCT2 (Organic Cation Transporter 2), is an electrogenic, voltage-dependent transporter that mediates the movement of various organic cations. These include endogenous bioactive amines, cationic drugs, and xenobiotics. It functions as a Na(+)-independent, bidirectional uniporter, meaning it can transport substances in both directions across the cell membrane without the involvement of sodium ions. The transport of cations is driven by the electrochemical potential gradient, which encompasses both the membrane potential and the concentration gradient. However, under saturating concentrations of cation substrates, SLC22A2 can also engage in electroneutral cation exchange. Primarily located at the basolateral membrane of hepatocytes and proximal tubules, SLC22A2 plays a role in the uptake and elimination of cationic compounds from the bloodstream through hepatic and renal clearance. It is involved in the uptake of monoamine neurotransmitters such as histamine, dopamine, adrenaline/epinephrine, noradrenaline/norepinephrine, serotonin, and tyramine, contributing to the regulation of neurotransmitter levels in the central nervous system. It also transports dopaminergic neuromodulators like cyclo(his-pro), salsolinol, and N-methyl-salsolinol, potentially contributing to the maintenance of dopaminergic cell integrity in the brain. SLC22A2 mediates the bidirectional transport of acetylcholine (ACh) at the apical membrane of ciliated cells in airway epithelium, contributing to the release of ACh into the airway lumen. Other transported substances include guanidine, endogenous monoamines like vitamin B1/thiamine, creatinine, and N-1-methylnicotinamide (NMN), the quaternary ammonium compound choline, the polyamine agmatine, and the polyamines putrescine and spermidine. Additionally, it can transport non-amine endogenous compounds such as prostaglandin E2 (PGE2) and prostaglandin F2-alpha (PGF2-alpha), and is involved in the uptake of the xenobiotic 4-(4-(dimethylamino)styryl)-N-methylpyridinium (ASP). SLC22A2 is believed to contribute to the regulation of organic compound transport across the blood-testis barrier in the testes.
SLC22A2 is also known as OCT2.
