Glycosylation effect on membrane domain (GEM) involved in cell adhesion and motility: A preliminary note on functional alpha 3, alpha 5-CD82 glycosylation complex in ldlD 14 cells

Laminin (LN)- or fibronectin (FN)-dependent adhesion in Krieger's ldlD 14 ( D14) cells is enhanced significantly in the presence vs absence, of galacto se (Gal), whereas LN- or FN-induced haptotactic cell motility is barely aff ected unless cells express CD82 by its gene transfection (cells termed D14/ CD82), The effect of CD82 on LN- or FN-induced motility is based on its abi lity to associate with alpha3 or alpha5 integrin to form a complex associat ed with a low-density lipid membrane domain (termed GEM or GSD), Complex fo rmation is greatly affected by N-glycosylation of both integrin and CD82, a s well as by concurrent GM3 ganglioside synthesis. The effect of glycosylat ion on alpha5-CD82 complex was also studied in D14 cells expressing mutant CD82, defective in all three N-glycosylation sites. LN-induced motility was greatly inhibited, whereas FN-induced motility was enhanced, with complete N-glycosylation in D14/CD82 cells in Gal-added medium, whereby alpha5-CD82 complex formation did not occur or occurred at a minimal level, Both LN- a nd FN-induced motility were inhibited when N-glycosylation was impaired, or N-glycosylation of CD82 was deleted, whereby alpha5-CD82 complex formation occurred strongly. Thus, glycosylation profoundly affects interaction of i ntegrin with CD82, leading to significant inhibition or promotion of cell m otility, (C) 2000 Academic Press.