Phorbol esters stimulate the phosphorylation of receptors for insulin and somatomedin C.

摘要: The effect of phorbol esters on the extent phosphorylation receptors for insulin and somatomedin C (insulin-like growth factor I) was studied in intact IM-9 cells that were labeled by incubation with H332PO4. tumor-promoting tetradecanoate acetate (TPA) dibutyrate, but not inactive 4 alpha-phorbol, enhanced beta subunit both approximately 4-fold; 70 nM TPA maximally stimulated receptors, whereas concentrations less than or equal to 0.7 had no observable effect. Insulin also receptor, its effects appeared be additive those TPA. Peptide maps indicated at least some residues phosphorylated these two agents are distinct. These results suggest a possible role protein kinase regulating receptors.