Cytokines & Growth Factors

Epidermal growth factor (EGF) is prototypic of a family of growth factors that are derived from membrane-anchored precursors. All members of this family are characterized by the presence of at least one EGF structural unit in their extracellular domain. The EGF structural unit is defined by the presence of a conserved six-cysteine motif that forms three disulfide bonds. EGF is initially synthesized as a 130 kDa precursor transmembrane protein containing nine EGF units. The mature soluble EGF sequence corresponds to the EGF unit located proximal to the transmembrane domain. The purified recombinant human EGF containing 54 amino acid residues is the N-terminal methionyl form of natural mature EGF and has a predicted molecular mass of approximately 6 kDa. A wide variety of in vitro and in vivo biological effects have been ascribed to EGF and other members of the EGF family. In vitro, EGF is a mitogen for fibroblasts, epithelial and endothelial cells, neuronal precursors, and promotes colony formation of epidermal cells in culture. In vivo, EGF induces epithelial development, promotes angiogenesis, and inhibits gastric acid secretion.