Unesterified long chain fatty acids inhibit the binding of single chain urokinase to the urokinase receptor

Oleic acid and other long chain fatty acids inhibit the binding of single chain urokinase (scuPA) with cultured trophoplasts, endothelial cells, and soluble urokinase receptor at physiological plasma concentrations. Such inhibitory effect is dose-dependent and saturable, consistent with the involvement of specific binding sites. Inhibition is maximal at the oleic acid concentration of 150 muM. The results suggests that unsaturated long chain fatty acids may act as physiological regulators of proteolytic events and intracellular signalling.