NCIt definition : Many Epidermal Growth Factor Superfamily Proteins are extracellular signaling molecules
(ligands) involved in control of target cell proliferation, cell survival, and cell
differentiation. The EGF superfamily is characterized by having at least 6 cysteines
residues that form disulphide bonds stacked in a ladder-like arrangement, in the order
1-3, 2-4, 5-6, and which are essential for the stability of the EGF fold. Often arranged
as tandem repeats in extracellular proteins, the function of the domains remains unclear,
but are thought to perform a structural role.;