SLC10A1

SLC10A1 is a human gene that encodes the Na+/taurocholate cotransporting polypeptide (NTCP), a member of the solute carrier 10 (SLC10) family. NTCP is a membrane transporter primarily expressed in hepatocytes and plays a central role in hepatic uptake of bile acids from portal blood.

NTCP mediates sodium-dependent transport of conjugated bile acids into liver cells. It largely handles conjugated bile acids such as taurocholate and glycocholate and operates by coupling bile acid uptake to the inward sodium gradient, with a stoichiometry that involves two Na+ ions per bile acid molecule. This transport is a key step in the enterohepatic circulation of bile acids and helps maintain bile acid homeostasis.

Expression is predominantly in the liver, with the transporter localized to the basolateral (sinusoidal) membrane of hepatocytes, facilitating uptake from the blood rather than secretion into bile. NTCP also contributes to the hepatic clearance of certain steroids and drugs that resemble bile acids.

Clinical significance includes its essential role in bile acid homeostasis and its function as a receptor for hepatitis B and D viruses; these viruses use NTCP to enter hepatocytes, making NTCP a target for antiviral strategies. Genetic variants that reduce NTCP activity can alter bile acid levels and liver transport dynamics, sometimes with hypercholanemia as a consequence. NTCP inhibitors are explored for therapeutic modulation of bile acid uptake and for antiviral applications, though they can impact drug and bile acid pharmacokinetics.