Regulation of human squamous cell carcinoma plasma membrane associated urokinase plasminogen activator by epidermal growth factor.

The amino terminal portion of urokinase type plasminogen activator (uPA) interacts with a cell surface binding protein/receptor that recognizes a region of the molecule autonomous from that of the catalytic domain of the enzyme, which mediates the conversion of plasminogen to plasmin. The expression of cell surface uPA receptors (uPA-Rs) and their association with uPA have been implicated in cellular invasion and tissue destruction. Treatment of A431 squamous carcinoma cells (SqCC) with epidermal growth factor (EGF) has previously been shown to result in an induction of the synthesis and extracellular accumulation of uPA and the plasminogen-dependent proteolysis of extracellular matrix (ECM).