title: Effects of phorbol ester on tyrosine hydroxylase phosphorylation and activation in cultured bovine adrenal chromaffin cells.
abstract: The phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) caused phosphorylation of phosphoproteins of 56-kDa which co-migrated with and had identical pI values to subunits of tyrosine hydroxylase. The phosphorylation was closely correlated with an increase of [3H]3,4-dihydroxyphenylalanine (DOPA) production which is a reflection of increased tyrosine hydroxylase activity. Only those phorbol esters which activate protein kinase C induced phosphorylation of the 56-kDa proteins and increased [3H]DOPA production. Neither TPA-induced phosphorylation of the 56-kDa proteins nor TPA-induced enhancement of [3H] DOPA production required extracellular Ca2+. TPA caused increases in phosphorylation of the 56-kDa proteins and increases in [3H]DOPA production over similar concentration ranges (10-1000 nM). TPA did not increase cellular cAMP. The data suggest that phorbol ester-induced phosphorylation of intracellular tyrosine hydroxylase, possibly by protein kinase C, results in increased tyrosine hydroxylase activity.
authors.forename: S L
authors.initials: SL
authors.lastname: Pocotte
authors.forename: R W
authors.initials: RW
authors.lastname: Holz
mesh_terms: D000313:Adrenal Medulla / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D002838:Chromaffin System / Q000187:drug effects* / Q000378:metabolism; D004295:Dihydroxyphenylalanine / Q000096:biosynthesis; D004789:Enzyme Activation / Q000187:drug effects; D010703:Phorbol Esters / Q000494:pharmacology*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000502:physiology; D011978:Receptors, Nicotinic / Q000502:physiology; D013268:Stimulation, Chemical; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
chemical_list: D010703:Phorbol Esters; D010750:Phosphoproteins; D011976:Receptors, Muscarinic; D011978:Receptors, Nicotinic; D004295:Dihydroxyphenylalanine; D014446:Tyrosine 3-Monooxygenase; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate