MODULATION OF FRUCTOSE-2,6-BISPHOSPHATE METABOLISM BY COMPONENTS OF THE EXTRACELLULAR-MATRIX IN CULTURED-CELLS - INTERACTION WITH EPIDERMALGROWTH-FACTOR

The use of NIH3T3 fibroblasts overexpressing different mutations of th e EGF receptor shows that regulation of fructose-2,6-bisphosphate (Fru -2,6-P-2) metabolism by EGF is mediated by the kinase activity of the EGF receptor and suggests a PLC gamma 1-mediated mechanism. The effect of several entracellular matrix components on glucose metabolism was assessed by incubating A431 cells and NIH3T3 fibroblasts with heparin, laminin, fibronectin, collagen and PG-I and PG-II proteoglycans and m easuring the levels of Fru-2,6-P-2. Laminin increased the levels of Fr u-2,6-P-2 and heparin decreased the levels of the metabolite, whereas the other molecules did not have any effect. No effect of laminin or h eparin in glucose uptake by the cell was observed, Laminin was able to modulate the effects of EGF on Fru-2,6-P-2 concentration, suggesting cross-talk between these agents. (C) 1997 Federation of European Bioch emical Societies.