Organic cation transporter 1, 2, and 3 (OCT1-3) (OCT1-3)

Organic cation transporters 1, 2, and 3 (OCT1–3) are essential membrane proteins belonging to the solute carrier family 22 (SLC22) that mediate the sodium-independent transport of various endogenous and exogenous organic cations (Source: UniProt P08190, O15245, O75751). OCT1 (SLC22A1) is primarily localized to the sinusoidal membrane of hepatocytes, where it is a major determinant of the hepatic uptake and efficacy of drugs such as metformin (Source: PubMed: 23535310). OCT2 (SLC22A2) is predominantly expressed in the basolateral membrane of renal proximal tubule cells, playing a pivotal role in the renal clearance of drugs and serving as a site for drug-induced nephrotoxicity, notably with cisplatin (Source: FDA Drug Development and Drug Interactions). OCT3 (SLC22A3) exhibits a more widespread tissue distribution, including the heart, brain, and placenta, and is involved in the extraneuronal uptake of monoamine neurotransmitters like dopamine and serotonin (Source: PubMed: 29111910). These transporters are critical for drug pharmacokinetics, and their inhibition or genetic variation can lead to significant drug-drug interactions or altered therapeutic outcomes (Source: StatPearls). Consequently, they are recognized by regulatory agencies as key targets for evaluating drug safety and disposition during development (Source: FDA Guidance 2020).

Other names

SLC22A1SLC22A2SLC22A3Solute carrier family 22 member 1Solute carrier family 22 member 2Solute carrier family 22 member 3Extraneuronal monoamine transporterEMTOCT1OCT2OCT3

Facilitated diffusion (uniporter) of organic cations across the plasma membrane down their electrochemical gradient (Source: PubMed: 23535310).