Organic anion-transporting polypeptides (OATPs) (OATPs)

Organic anion-transporting polypeptides (OATPs), encoded by the SLCO gene superfamily, are integral membrane transporters with 12 transmembrane domains that mediate the sodium-independent uptake of amphipathic organic anions, including drugs, bile acids, steroid conjugates, thyroid hormones, and bilirubin, primarily via an anion-exchange mechanism involving bicarbonate or glutathione. Expressed on basolateral or apical membranes in key tissues like liver, intestine, kidney, and brain, OATPs play a central role in drug absorption (e.g., intestinal OATP2B1), hepatic clearance (e.g., OATP1B1/1B3), and distribution, influencing pharmacokinetics of statins, anticancer agents, and antihypertensives. Dysregulation or inhibition contributes to drug-drug interactions, reduced efficacy, and variability from SLCO polymorphisms, while cancer-specific overexpression positions certain OATPs as anticancer targets or vectors for prodrug delivery. Their broad substrate specificity and pH sensitivity add complexity to pharmacotherapy, spurring research into selective modulators.

Other names

organic anion transporting polypeptidesOATP familySLCO familysolute carrier organic anion transporters

Facilitated Na+-independent transport of amphipathic organic anions (>350 Da); anion exchange; uptake into hepatocytes, enterocytes, astrocytes; targeted by inhibitors or prodrugs for enhanced delivery.