asialoglycoprotein receptor activity

Definition

Target type: molecularfunction

Receiving an asialoglycoprotein, and delivering the asialoglycoprotein into the cell via endocytosis. An asialoglycoprotein is a plasma glycoproteins from which the terminal sialic acid residue on their complex carbohydrate groups has been removed. The asialoglycoprotein receptor recognizes the terminal galactose and N-acetylgalactosamine units of the asialoglycoprotein, the receptor-ligand complex is internalized and transported to a sorting organelle where disassociation occurs before the receptor is recycled to the cell membrane. [GOC:bf, PMID:11278827, PMID:7624395, Wikipedia:Asialoglycoprotein]

Asialoglycoprotein receptor (ASGPR) activity is a critical molecular function involved in the clearance of circulating glycoproteins from the bloodstream. ASGPRs are transmembrane proteins primarily expressed on the surface of hepatocytes, the main cell type in the liver. These receptors recognize and bind to glycoproteins that have lost their terminal sialic acid residues, termed asialoglycoproteins. The loss of sialic acid exposes galactose residues on the glycoproteins, which are recognized by the ASGPRs. Binding of asialoglycoproteins to ASGPRs initiates a process called receptor-mediated endocytosis. This process involves the invagination of the plasma membrane, forming a vesicle that encapsulates the bound glycoproteins. The vesicle then transports the glycoproteins into the cytoplasm of the hepatocyte. Once inside the cell, the asialoglycoproteins are delivered to lysosomes, where they are degraded into their constituent amino acids and sugars. This ASGPR-mediated clearance pathway plays a critical role in maintaining the homeostasis of circulating glycoproteins, removing damaged or aged proteins, and preventing the accumulation of potentially harmful molecules. It is also crucial for the metabolism of certain glycoproteins, such as hormones and enzymes. Mutations or deficiencies in ASGPR activity can lead to various disorders, including accumulation of asialoglycoproteins in the blood, altered protein metabolism, and liver dysfunction.'
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Proteins (1)

Compounds (2)