82 Transmembrane signal transduction Concept ● Several main forms ck Mediated by ion channel k Mediated by g-protein coupled receptor k Mediated by tyrosine kinase receptor k Mediated by intercellular channel k Mediated by nitric oxide o Cellular proto-oncogene Mediate-early gene§ 2. Transmembrane signal transduction • Concept • Several main forms * Mediated by ion channel * Mediated by G-protein coupled receptor * Mediated by tyrosine kinase receptor * Mediated by intercellular channel * Mediated by nitric oxide • Cellular proto-oncogene Mediate-early gene