title: Protein kinase C mediated phosphorylation blocks juvenile hormone action.
abstract: Juvenile hormones (JH) regulate a wide variety of developmental and physiological processes in insects. Although the biological actions of JH are well documented, the molecular mechanisms underlying JH action are poorly understood. We studied the molecular basis of JH action using a JH response element (JHRE) identified in the promoter region of JH esterase gene cloned from Choristoneura fumiferana, which is responsive to JH and 20-hydroxyecdysone (20E). In Drosophila melanogaster L57 cells, the JHRE-regulated reporter gene was induced by JH I, JH III, methoprene, and hydroprene. Nuclear proteins isolated from L57 cells bound to the JHRE and exposure of these proteins to ATP resulted in a reduction in their DNA binding. Either JH III or calf intestinal alkaline phosphatase (CIAP) was able to restore the binding of nuclear proteins to the DNA. In addition, protein kinase C inhibitors increased and protein kinase C activators reduced the binding of nuclear proteins to the JHRE. In transactivation assays, protein kinase C inhibitors induced the luciferase gene placed under the control of a minimal promoter and the JHRE. These data suggest that protein kinase C mediated phosphorylation prevents binding of nuclear proteins to juvenile hormone responsive promoters resulting in suppression of JH action.
authors.affiliation: Department of Entomology, College of Agriculture, University of Kentucky, Lexington, KY 40546, USA.
authors.forename: Damu R
authors.initials: DR
authors.lastname: Kethidi
authors.forename: Yiping
authors.initials: Y
authors.lastname: Li
authors.forename: Subba R
authors.initials: SR
authors.lastname: Palli
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002417:Cattle; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D004331:Drosophila melanogaster; D004441:Ecdysterone / Q000494:pharmacology; D020536:Enzyme Activators / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D017930:Genes, Reporter; D007605:Juvenile Hormones / Q000502:physiology*; D007915:Lepidoptera; D008726:Methoprene / Q000494:pharmacology; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D020218:Response Elements; D015398:Signal Transduction
chemical_list: D020536:Enzyme Activators; D005231:Fatty Acids, Unsaturated; D007605:Juvenile Hormones; D009687:Nuclear Proteins; D047428:Protein Kinase Inhibitors; C006481:ethyl-3,7,11-trimethyl-2,4-dodecadienoate; D004441:Ecdysterone; D008726:Methoprene; D000255:Adenosine Triphosphate; D004247:DNA; D011493:Protein Kinase C; D000469:Alkaline Phosphatase