Organic anion transporting polypeptide 1B3 (OATP1B3)

Organic anion transporting polypeptide 1B3 (OATP1B3) is an integral membrane transporter protein encoded by the *SLCO1B3* gene, primarily expressed on the basolateral (sinusoidal) membrane of human hepatocytes[1][8]. It mediates the sodium-independent facilitated uptake of a wide range of endogenous compounds (such as bilirubin, bile acids, conjugated steroids, eicosanoids, thyroid and peptide hormones) and structurally diverse drugs (including several statins, chemotherapeutics, and other small molecules) from the blood into the liver for subsequent metabolism and biliary excretion[1][3][4][8]. OATP1B3 displays broad substrate specificity and significant overlap with OATP1B1. It is a major determinant of hepatic drug clearance and a central player in pharmacokinetic drug-drug interactions, with clinically relevant polymorphic variants that can affect drug response and toxicity, notably increasing the risk of statin-induced adverse events[3][4]. OATP1B3 is also ectopically expressed in some cancers, affecting chemotherapy distribution[5][6]. Its expression and function are regulated by nuclear receptors and affected by genetic polymorphisms, making it an important molecular target and biomarker in both toxicology and precision medicine[1][8].

Other names

Solute carrier organic anion transporter family member 1B3SLCO1B3OATP8 (outdated)

Uptake of drugs and endogenous molecules into hepatocytes via facilitated diffusion Modulation of drug plasma and tissue concentrations through hepatic clearance Mediation of drug-drug interactions by serving as entry point for substrate/inhibitor competition