Ligand-induced dimerization of growth factor receptors: variations on the theme.

Growth, differentiation, apoptosis and movement of cells are regulated, in part, by polypeptide growth factors, or cytokines, which exert their effects by binding to cell surface receptors on the target cells. Recent observations have indicated that a common mechanism of activation of several classes of such receptors is ligand-induced dimerization or oligomerization of the receptors.