Epidermal growth factor-receptor interaction in rat pheochromocytoma (PC12) and human epidermoid A431 cells: Biochemical and ultrastructural studies

Pheochromocytoma cells (clone PC12) have specific plasmamembrane receptors for both epidermal growth factor (EGF) and nerve growth factor (NGF). These growth factors have however, opposite biological effects in PC12 cells; EGF acts mitogenically, while NGF induces differentiation and causes arrest of cell proliferation. EGF-receptor interaction in PC12 cells was characterized biochemically by ¹²⁵I-EGF binding studies. EGF binding was concentration-dependent and saturable. Scatchard graph analysis indicated that two different classes of EGF binding sites may be present in PC12 cells. Addition of NGF to PC12 cells caused a reduction in EGF binding, the result of a decrease of the number of binding sites and in their affinity for EGF. The reduction of EGF binding was dependent upon the duration and concentration of NGF exposure