Bile salt export pump (ABCB11) (BSEP)

The Bile salt export pump (ABCB11), also known as BSEP, is the primary transport protein responsible for the secretion of bile acids from hepatocytes into the bile canaliculi. As a member of the ATP-binding cassette (ABC) transporter family, it utilizes ATP hydrolysis to move bile salts against a steep concentration gradient, which is the rate-limiting step in bile formation and essential for the enterohepatic circulation of bile acids (UniProt: O95342). Dysfunction of BSEP, whether through genetic mutations or drug-induced inhibition, leads to the accumulation of toxic bile acids within the liver, resulting in cholestasis and severe hepatocellular injury (PubMed: 10359813). Genetic defects in the ABCB11 gene cause Progressive Familial Intrahepatic Cholestasis type 2 (PFIC2), a condition often requiring liver transplantation in childhood. In drug development, BSEP is a critical safety target; many drugs associated with drug-induced liver injury (DILI), such as bosentan and troglitazone, are known to inhibit BSEP activity (PubMed: 12482951). Conversely, therapeutic strategies for cholestatic diseases often involve inducing BSEP expression through the activation of the Farnesoid X receptor (FXR), which serves as its primary transcriptional regulator (PubMed: 23714154). Note: The provided name 'Bile acid secretion' refers to a physiological process rather than a single molecular target, but BSEP is the canonical protein responsible for this function.

Other names

ABCB11ATP-binding cassette sub-family B member 11Sister of P-glycoproteinsPgpPGY11

Inhibition of ATP-dependent bile salt transport; Induction of protein expression via PXR/FXR activation.