title: Insulin secretion and protein phosphorylation in PKC-depleted islets of Langerhans.
abstract: Protein kinase C (PKC)-dependent phosphorylation of endogenous substrates was measured in electrically permeabilised rat islets of Langerhans. The PKC-activating phorbol ester, 4 beta-phorbol myristate acetate (PMA), caused a slow but prolonged increase in insulin secretion from permeabilised islets, which was accompanied by increased 32P incorporation into several islet proteins of apparent M.W. 30-50 kDa. Depletion of islet PKC by prolonged exposure to PMA abolished subsequent secretory and phosphorylating responses to the phorbol ester. However, PKC-depleted islets did not show diminished responses to glucose, suggesting that PKC-mediated phosphorylation of these proteins is not essential for nutrient-induced insulin secretion.
authors.affiliation: Biomedical Sciences Division, King's College, London, U.K.
authors.forename: P M
authors.initials: PM
authors.lastname: Jones
authors.forename: S J
authors.initials: SJ
authors.lastname: Persaud
authors.forename: S L
authors.initials: SL
authors.lastname: Howell
mesh_terms: D000818:Animals; D001345:Autoradiography; D003720:Densitometry / Q000379:methods; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D010539:Permeability; D010766:Phosphorylation; D011493:Protein Kinase C / Q000187:drug effects / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D007328:Insulin; D011506:Proteins; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate