Cholangiocyte plasma membrane

The cholangiocyte plasma membrane refers to the polarized cell surface of cholangiocytes, the epithelial cells lining intrahepatic and extrahepatic bile ducts, divided into apical (luminal) and basolateral domains separated by tight junctions that maintain epithelial polarity. This membrane hosts critical transporters and channels enabling cholangiocytes' primary role in modifying primary hepatocyte-derived bile through vectorial secretion of bicarbonate-rich fluid and reabsorption of solutes like bile acids, glucose, and amino acids. Key apical components include CFTR (cAMP-regulated Cl⁻ channel), AE2 (Cl⁻/HCO₃⁻ exchanger), AQP1 (water channel), ASBT (Na⁺-dependent bile acid transporter), and PMCA (Ca²⁺ pump), while basolateral elements feature AQP4, Ostα-Ostβ (bile acid exporters), GLUT1 (glucose transporter), and receptors like secretin receptor driving cAMP signaling for secretion. Heterogeneity exists between small (proliferative, Ca²⁺-sensitive) and large (secretory, cAMP-responsive) cholangiocytes, influencing membrane protein expression and function. Dysfunctions in these membrane mechanisms contribute to diseases like cholangiocarcinoma and cholestasis, but the membrane itself is not a discrete therapeutic target; instead, specific embedded proteins (e.g., CFTR) are pursued.

Other names

Bile duct epithelial cell membraneCholangiocyte apical membraneCholangiocyte basolateral membrane