Ganglioside cells, binding

Table V. Effect of Gangliosides on Binding of Choleragen to Cells ...

Superti F, Donelli G (1991) Gangliosides as binding sites in SA-11 rotavirus infection of LLC-MK2 cells. J Gen Virol 72 2467-2474... 

Caveolae can mediate the delivery of CtxB that binds to GM1 ganglioside at the plasma membrane and is delivered to intracellular compartments. Cholera toxin, produced by Vibrio cholerae, consists of five identical subunits B and one A chain. In addition to labeled SV40 and caveolin-1-GFP, CtxB is one of the most commonly used caveolae markers. However, two groups reported that the toxin is internalized by either a clathrin-independent caveolae pathway or a clathrin-dependent uptake, bringing its selectivity/specificity into question (31,81,118). We controlled the suitability of this marker for COS-7 cells pretreated with CPZ, mpCD, and filipin and as expected, the uptake was not influenced by CPZ treatment but was strongly decreased by the latter two (data not shown). 

Mucosal adjuvants Bind to M cells and GMl ganglioside receptors on mucosal epithelium CT toxin... 

The nonpolar ceramide chains of the ganglioside are buried in the membrane bilayer. The initial tight binding (fQ 2 x 107 M-1) of the toxin is followed by a poorly understood process in which the A subunit enters the cell. The peptide chain of this subunit is... 

Ellipsometry can follow the interactions between two types of biological macromolecules, the first of those two bound physically to the surface, the other acting from the solution. The binding of conconavalin A to adsorbed mannan 180) and of cholera toxin to adsorbed ganglioside t83) are examples. The adsorption of complement factors to an antibody-coated surface was monitored by ellipsometry and a modification of the same method was used for quantification of migration inhibition of human polymorphonuclear leucocytes 182). Interaction of proteins and cells with affinity ligands covalently coupled to silicon surfaces has been also studied 183). 

The induction of toxin receptors by butyrate also occurred in serum-free medium (5). Serum contains gangliosides including GM1 and GM1-deficient cells can absorb GM1 from serum and become responsive to choleragen (22). Cells exposed simultaneously to butyrate and cyc1oheximide""cTid not exhibit an increase in choleragen binding (unpublished observations). Thus, butyrate appears to induce toxin receptors de novo in a manner analogous to the induction of GM3. 

Exogenous GM1 ganglioside can be incorporated into the cell membrane and then act as a functional receptor. This was first shown by Cuatrecasas (11) who observed an increased binding capacity and lipolytic responsiveness of fat cells which had been soaked in GM1. Using tritium-labelled GM1-ganglioside, Holmgren... 

Chemical modifications of cholera toxins by means of various reagents were consistently found to affect binding to cells and to GM1 ganglioside to the same extent (lU). 

That T-cell Interferon does not bind to gangliosides is demonstrated by its behavior on ganglioside affinity columns ... 

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