Inhibition by transmembrane peptides of chimeric insulin receptors.

Receptor tyrosine kinases play essential roles in cell proliferation and differentiation. We have recently shown that peptides corresponding to the transmembrane domains of the epidermal growth factor (EGF) and ErbB2 receptors inhibit their corresponding receptor activation in cancer cell lines. We extend this observation to cells transfected with chimeric insulin receptors where the transmembrane domain has been replaced by that of the EGF receptor or a mutated Erb2 domain. Peptides corresponding to the transmembrane domains of the EGF receptor and ErbB2 are able to inhibit specifically the autophosphorylation of insulin receptors with the corresponding domain. This inhibitory effect is correlated with the propensity of the different transmembrane domains to self-associate in a genetic reporter assay. Thus, our data strengthen the notion that transmembrane domains are involved in erbB receptor activation, and that these receptors can be modulated by inhibiting protein-protein interactions within the membrane.