Effect of membrane lipid composition and microtubule structure on lectin interactions of mouse lm cells

Abstract

Concanavalin A (Con A) binding and Con A-mediated hemadsorption t o LM cells were found t o decrease significantly at both 5-7'C and 15-19'C. The higher of these critical temperatures responds t o a change in state of the membrane lipids and can be increased or decreased in cells where the membrane phospholipids contain less or more double bonds, respectively. The lower critical temperature for Con A binding or Con A-mediated hemadsorption does not respond t o these changes in membrane lipid composition. Though the amount of Con A bound t o the cell surface is a determinant of Con A-mediated agglutinability, the major components of the decreases in Con A-mediated hemadsorption which occur at both these critical temperatures do not have their origin in the decreases ip Con A bindi!g which occur over these same temperature ranges -that is 5-7 C and 15-19 C. , Con A-mediated hemadsorption measured at 22OC was dramatically inhibited when LM cells were first incubated at 7'C or less. Reversal of this inhibition required 20-30 min of subsequent incubation at 22"C, indicating that factors other than membrane lipid "fluidity" are determinants of agglutinability. LM cells treated with the microtubule-disrupting alkaloids colchicine, colcemid, or vinblastine at concentrations as low as agglutinable with Con A. By contrast, lumicolchicine, an inactive derivative of colchicine, had a slight inhibitory effect on Con A-mediated hemadsorption. Colchicine, vinblastine, or lumicolchicine treatment of LM cells did not alter the quantitative binding of labeled lectin. The results suggest that membrane lipid "fluidity" and the cell cytoskeleton (microtubule/microfilament system) are important determinants of lectin interactions with cell surfaces. The results are interpreted in terms of a model of cell-cell and cell-lectin interactions which assigns a central role t o the Con A receptor.

Phospholipid polar head group manipulation modulates concanavalin A agglutinability of LM fibroblasts

“…The effect of microtubule and microfilament disrupting drugs and anesthetic agents on Con A mediated LM cell agglutinability was tested (Table VI). Both anesthetics (ethanol and pentobarbital) that fluidize membranes (Harris & Schroeder, 1981 and microtubule disrupting drugs such as colchicine (Rittenhouse et al, 1974b) enhanced agglutinability of LM cells by shortening the lag time. Longer exposure of cells to colchicine (1.25-24 h at 0.1-10 X 10-6 M) also resulted in shortened lag times (data not shown).…”

Fluidity of LM cell membranes with modified lipid compositions as determined with 1,6-diphenyl-1,3,5-hexatriene

“…The changes in the phospholipid composition occur in all the membrane fractions of the cell (Schroeder et al, 1976c). Changes in the phospholipid polar head-group and fatty acid composition in these cells have been shown to alter adenylate cyclase activity (Engelhard et al, 1976), stearoyl-CoA desaturase activity (Blank et al, 1976), and lectin interactions (Rittenhouse et al, 1974). In addition, the level of sterol present in the membrane can be altered and this can influence endocytosis (Heiniger et al, 1976) and Rb+ transport (Chen et al, 1978).…”