Signal Transduction by Growth Factor Receptors

Abstract

The proliferation of cells in vivo and in culture is tightly regulated by polypeptide growth factors. Like all polypeptide hormones, growth factors initiate their action by binding to specific, high affinity receptor molecules on the cell surface. Interest in growth factors and their receptors has been dramatically intensified by the discovery that at least some of these molecules show a striking structural homology with certain viral oncogene products. For example, the sis oncogene encodes a platelet-derived growth factor (PDGF) molecule, while the erb-B oncogene product is a truncated form of the receptor for epidermal growth factor (EGF) (Waterfield et al, 1983; Schlessinger 1986). Inappropriate expression of the cellular counterparts of viral oncogenes is thought to be responsible for the initiation and maintenance of malignant growth. Therefore, the study of the mode of action of growth factors will undoubtedly yield important insight into the mechanisms underlying carcinogenesis.