Receptor for lectins

Two lectins, one isolated from the horseshoe crab, Limulus poly-phemus (Pardoe and Uhlenbruck, 1970 Marchalonis and Edelman, 1968), and the other from wheat germ, Triticum vulgaris (Greenaway and LeVine, 1973 Bhavanandan and Davidson, 1975 Matsumoto and Codington, unpublished results), may attach at the cell periphery to receptor sites that include terminal glycoprotein-bound sialic acid units. The horseshoe crab lectin, purified and characterized by Marchalonis and Edelman (1968), was found by Pardoe and Uhlenbruck (1970) to be specific for terminal sialic acid residues. 

The specificity of wheat germ agglutinin has been attributed to bound N-acetylglucosamine residues, since this component, both as a 

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Glycophorin A appears to serve a variety of functions on the red-cell membrane, and has been implicated in several red-cell disorders. Because it extends from the external environment of the cell into the cell cytoplasm, it is considered to constitute a receptor for malarial parasites,"" influenza viruses, lectins, and Portuguese man-of-war toxin. Many of these receptor functions are attributable to the carbohydrate composition of these... 

Importantly, the internal diffusion model for lectins binding to mucins is distinct from the classical lock and key model of ligand binding to a receptor. The internal... 

Teraguchi, S., Shin, K., Fukuwatari, Y., and Shimamura, S. (1996). Glycans of bovine lacto-ferrin function as receptors for the type 1 fimbrial lectin of Escherichia coli. Infect. Immun. 64,1075-1077. 

Another important assumption from the lectin binding studies was that hemopoietic stem cells in the mouse may carry receptors for both peanut agglutinin and soybean agglutinin. Evidence in support of this assumption was obtained when, with the aid of peanut agglutinin and soybean agglutinin a cell fraction was isolated from mouse bone marrow and spleen, which was enriched with hemopoietic stem cells and depleted of "graft-versus-host" activity. Furthermore, such a cell fraction could be used for successful reconstruction of irradiated allogeneic mice (3SH. ... 

These same surface glycoproteins have been modeled as receptors for antibody molecules and in the binding of lectin molecules, such as concanavalin A. On the lymphocyte membrane,... 

Polypeptides are substrates for receptor-mediated transcytosis. Cerebral insulin reaches the brain from the circulation via receptor-mediated transcytosis through the BBB on the brain endothelial insulin receptor. This receptor is upregulated in development and downregulated in streptozotocin-induced diabetes mellitus. Similarly a BBB transferrin receptor mediates the transcytosis of transferrin across the BBB and this explains how the brain is able to extract iron from the circulation. Other RMT pathways consituting portals of entry to the brain for circulating peptides include receptors for insulin-like growth factors, cationic proteins, lectins, acetyl-low density lipoprotein and leptin. 

In the context of dmg delivery, certain cell surface receptor and ion-channel families are particularly appealing as dmg delivery targets. Well-characterized examples include the lectin-like receptor gene family as receptors for glycosylated molecules, as well as vitamin- and trace element-uptake systems such as the transferrin-receptor. 

The BS I that had been 125I-labeled by a diazonium coupling technique626 was employed in a study of lectin-receptor density on the B erythrocyte.191 Scatchard analysis of the binding data demonstrated a variation in receptor density among type B individuals from 7.2 X 104 to 13.4 X 104 sites per erythrocyte.191 Likewise, apparent association-constants for lectin-cell interaction varied from 1.1 X 107 to 2.9 X 107 M ... 

Extracellular or cell surface membrane receptors for D-galactose are widespread among higher eukaryotes. Isothermal titration calorimetry of the C-type lectin receptors from the tunicate Polyandrocatpa misakiensis revealed the presence of a single calcium atom per monomer with a dissociation constant of 2.6 pM, and confirmed the monosaccharide speci-... 

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