Study of structural-functional arrangement of the adenylyl cyclase signaling mechanism of action of insulin-like growth factor 1 revealed in muscle tissue of representatives of vertebrates and invertebrates

Based on the earlier discovered by the authors adenylyl cyclase signaling mechanisms (ACSM) of action of insulin and relaxin, a study was performed of the existence of a similar action mechanism of another representative of the insulin superfamily-the insulin—like growth factor 1 (IGF-1) in the muscle tissue of vertebrates (rat) and invertebrates (mollusc). For the first time there was detected participation of ACSM in the IGF-1 action, including the six-component signaling cascade: receptor tyrosine kinase → Gi-protein (βγ-dimer) → phosphatidylinositol-3-kinase (PI-3K) → protein kinase Cζ (PKCζ) → Gs-protein → adenylyl cyclase. By structural-functional organization at postreceptor stages, it coincides completely with that of insulin and relaxin, which we revealed in rat skeletal muscle. In smooth muscle of the mollusc Anodonta cygnea this ACSM of action of IGF-1 has only one difference-the protein kinase C included in this mechanism is represented not by the PKCζ isoform, but by another isoform close to PKCε of the vertebrate brain. Earlier we revealed the same differences in muscles of this mollusc in the ACSM of action of insulin and relaxin.