ATP-binding cassette subfamily B member 11 (ABCB11)

ATP-binding cassette subfamily B member 11 (ABCB11), also known as the bile salt export pump (BSEP), is a critical transporter protein located in the canalicular (apical) membrane of hepatocytes. It is responsible for the ATP-dependent export of bile salts from the cytoplasm into the bile canaliculi, constituting the rate-limiting step in bile formation and maintaining enterohepatic circulation[1][2][3][4][6]. Dysfunction or inhibition of ABCB11 can result in accumulation of toxic bile salts within hepatocytes, leading to various forms of intrahepatic cholestasis, increased risk of hepatocellular carcinoma, and severe liver diseases such as PFIC2 and BRIC2. Mutations in the ABCB11 gene or drug-induced inhibition are both common causes of ABCB11 dysfunction[2][6]. ABCB11 function is regulated primarily by transcriptional control through bile acid sensors such as the farnesoid X receptor (FXR)[3]. Pharmacological targeting of ABCB11 remains an area of active research, particularly in the context of protecting its function from drug interactions or compensating for genetic defects.

Other names

Bile salt export pumpBSEPSister P-glycoprotein (sPgp)ABC16SPGPPFIC-2PGY4Progressive familial intrahepatic cholestasis 2 proteinBenign recurrent intrahepatic cholestasis 2 proteinBRIC2MDR/TAP subfamily protein

Inhibition of ABCB11 reduces bile salt export, potentially leading to intracellular bile salt accumulation and cholestatic liver injury[6].\nSome drugs act as competitive or non-competitive inhibitors of BSEP.\nCertain small molecules (pharmacological chaperones and potentiators) may rescue trafficking defects in mutated BSEP[4].