J. Biol. Chem., Vol. 262, Issue 7, 3022-3029, 03, 1987

The chicken receptor for endocytosis of glycoproteins contains a cluster of N-acetylglucosamine-binding sites

JA Loeb and K Drickamer

The oligomeric state of the chicken hepatic receptor for N- acetylglucosamine-terminated glycoproteins (the chicken hepatic lectin) has been examined in detergent solution, in various membrane preparations, and in hepatocytes. In detergent solution, the cross- linking reagent, 1,5-difluoro-2,4-dinitrobenzene produces covalent complexes containing up to six receptor polypeptides. This result, along with hydrodynamic studies of the receptor-detergent complex, indicates that the purified receptor is a hexamer. Analysis of large proteolytic fragments of the receptor reveals that portions of the receptor polypeptide near the membrane anchor are essential for hexamer stability. This analysis also demonstrates that each receptor polypeptide has an N-acetylglucosamine-binding site, indicating that the native hexameric receptor contains a cluster of six such sites. Immunoblot analysis of membrane fractions and cells cross-linked with 1,5-difluoro-2,4-dinitrobenzene or dimethyl adipimidate reveals that the receptor is also oligomeric in intact cells and in subcellular fractions representing cell surface and internalized receptor. Although the pattern of cross-linking observed in membranes differs from that observed with purified receptor, experiments indicate that the differences may be explained by the presence of membrane components which compete with receptor for reaction with cross-linking reagent. The presence of a cluster of carbohydrate-binding sites in the hepatocyte membrane can account for the preferential endocytosis of multivalent glycoprotein ligands by hepatocytes.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				R. Gurezka, R. Laage, B. Brosig, and D. Langosch A Heptad Motif of Leucine Residues Found in Membrane Proteins Can Drive Self-assembly of Artificial Transmembrane Segments J. Biol. Chem., April 2, 1999; 274(14): 9265 - 9270. [Abstract] [Full Text] [PDF]

				D. Beasley COX-2 and cytosolic PLA2 mediate IL-1beta -induced cAMP production in human vascular smooth muscle cells Am J Physiol Heart Circ Physiol, April 1, 1999; 276(4): H1369 - H1378. [Abstract] [Full Text] [PDF]

				B. Arunachalam and P. Cresswell Molecular Requirements for the Interaction of Class II Major Histocompatibility Complex Molecules and Invariant Chain with Calnexin J. Biol. Chem., February 10, 1995; 270(6): 2784 - 2790. [Abstract] [Full Text] [PDF]

				W. Weis, R Kahn, R Fourme, K Drickamer, and W. Hendrickson Structure of the calcium-dependent lectin domain from a rat mannose-binding protein determined by MAD phasing Science, December 13, 1991; 254(5038): 1608 - 1615. [Abstract] [PDF]