Organic cation transporter 1, Organic cation transporter 2, Organic cation transporter 3 (OCT1, OCT2, OCT3)

Organic cation transporter 1, 2, and 3 (OCT1, OCT2, and OCT3) are members of the solute carrier family 22 (SLC22) of membrane proteins. They are polyspecific transporters responsible for the uptake and clearance of a wide variety of endogenous amines (e.g., choline, monoamines) and diverse cationic drugs from blood into tissues including the liver, kidney, and brain. OCT1 is primarily expressed in the liver, OCT2 in the kidney, and OCT3 in many tissues including heart, brain, and placenta. Their broad substrate specificity and high expression make them key determinants of drug absorption, distribution, elimination, and drug-drug interactions. Genetic and functional variations in these transporters can have major consequences for drug efficacy, adverse reactions, and toxicity profiles. They are therefore considered clinically important drug transporters and therapeutic modulation or inhibition of their function can have significant pharmacological and toxicological implications

Other names

SLC22A1 (OCT1)SLC22A2 (OCT2)SLC22A3 (OCT3)organic cation transporter(s)polyspecific organic cation transporter(s)

Substrate drugs are transported across cell membranes via electrogenic facilitated diffusion - Inhibitors block substrate binding or transporter conformational changes, reducing uptake