Asialoglycoprotein receptor (ASGPR)

The **Asialoglycoprotein receptor** (ASGPR) is a transmembrane, C-type lectin receptor primarily expressed on the surface of mammalian hepatocytes. Composed of two homologous subunits (ASGR1 and ASGR2), it forms hetero-oligomeric complexes that bind glycoproteins with exposed galactose or N-acetylgalactosamine (GalNAc) residues after the removal of terminal sialic acids. This interaction, requiring calcium ions, mediates high-affinity, clathrin-dependent endocytosis and lysosomal degradation of circulating glycoproteins, contributing to plasma protein homeostasis and liver metabolic functions[1][3][2][4][7]. ASGPR also serves as a viral entry factor (e.g., for hepatitis B and C viruses and SARS-CoV-2), a biomarker of hepatocellular differentiation, and a validated target for hepatocyte-directed drug delivery platforms such as GalNAc-conjugated nucleic acid therapeutics and imaging agents. Dysregulation or loss of ASGPR function is implicated in liver diseases, altered cholesterol metabolism, and modified therapeutic response in hepatic targeting[7][8][9].

Other names

Hepatic lectinAsialoglycoprotein receptor 1ASGR1Asialoglycoprotein receptor 2ASGR2ASGP receptorLiver lectin

Ligand binding to exposed galactose or N-acetylgalactosamine (GalNAc) on glycoproteins triggers clathrin-mediated endocytosis and lysosomal degradation[7][3][1] Drug conjugates exploit receptor-mediated hepatocyte uptake for liver-specific delivery[9]