Asialoglycoprotein receptor

The asialoglycoprotein receptors are lectins which bind asialoglycoprotein and glycoproteins from which a sialic acid has been removed to expose galactose residues. The receptors, which are integral membrane proteins and are located on mammalian hepatocytes (liver cells), remove target glycoproteins from circulation.[1] The asialoglycoprotein receptor has been demonstrated to have high expression on the surface of hepatocytess,[2] several human carcinoma cell lines[3] It is also weakly expressed by glandular cells of the gallbladder[2] ] and the stomach.[2] Lactobionic acid has been used as a targeting moiety for drug delivery to cells expressing asialoglycoprotein receptors.[4]

asialoglycoprotein receptor 1
Identifiers
SymbolASGR1
NCBI gene432
HGNC742
OMIM108360
RefSeqNM_001671
UniProtP07306
Other data
LocusChr. 17 p13-p11
asialoglycoprotein receptor 2
Identifiers
SymbolASGR2
NCBI gene433
HGNC743
OMIM108361
RefSeqNM_080914
UniProtP07307
Other data
LocusChr. 17 p

The asialoglycoprotein receptor contains two subunits, asialoglycoprotein receptor 1 (ASGR1) and asialoglycoprotein receptor 2 (ASGR2). These subunits may form different quaternary forms such as dimers, trimers, tetramers to allow for specific substrate binding or endocytosis. ASGR 1 is the major subunit and has 8 exons and is roughly 6 kb in length. ASGR 2 is the minor subunit and has 9 exons and is about 13.5 kb long. [5]

Function

Asialoglycoprotein receptors function to catabolize galactosyl and N-acetylgalactosaminyl-containing substrates.[1]

References
  1. Gupta GS, ed. (2012). Animal Lectins: Form, Function and Clinical Applications. Wien: Springer-Verlag. doi:10.1007/978-3-7091-1065-2.pdf.
  2. "ASGR1 Tissue". Human Protein Atlas.
  3. "ASGR1 Cell Lines". Human Protein Atlas.
  4. Roggenbuck D, Mytilinaiou MG, Lapin SV, Reinhold D, Conrad K (December 2012). "Asialoglycoprotein receptor (ASGPR): a peculiar target of liver-specific autoimmunity". Auto- Immunity Highlights. 3 (3): 119–125. doi:10.1007/s13317-012-0041-4. PMC 4389076. PMID 26000135.
  5. Harris RL, van den Berg CW, Bowen DJ (2012-08-02). "ASGR1 and ASGR2, the Genes that Encode the Asialoglycoprotein Receptor (Ashwell Receptor), Are Expressed in Peripheral Blood Monocytes and Show Interindividual Differences in Transcript Profile". Molecular Biology International. 2012: 283974. doi:10.1155/2012/283974. PMC 3419429. PMID 22919488.
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