title: Protein kinase C modulates ecdysteroidogenesis in the prothoracic gland of the tobacco hornworm, Manduca sexta.
abstract: The prothoracic gland is the primary source of ecdysteroid hormones in the immature insect. Ecdysteroids coordinate gene expression necessary for growth, molting and metamorphosis. Prothoracicotropic hormone (PTTH), a brain neuropeptide, regulates ecdysteroid synthesis in the prothoracic gland. PTTH stimulates ecdysteroid synthesis through a signal transduction cascade that involves at least four protein kinases: protein kinase A (PKA), p70 S6 kinase, an unidentified tyrosine kinase, and the extracellular signal-regulated kinase (ERK). In this report, the participation of protein kinase C (PKC) in PTTH signalling is demonstrated and characterized. PTTH stimulates PKC activity through a PLC and Ca(2+)-dependent pathway that is not cAMP regulated. Inhibition of PKC inhibits PTTH-stimulated ecdysteroidogenesis as well as PTTH-stimulated phosphorylation of ERK and its upstream regulator, MAP/ERK kinase (MEK). These observations reveal that the acute regulation of prothoracic gland steroidogenesis is dependent on a web of interacting kinase pathways, which probably converge on factors that regulate translation.
authors.affiliation: Department of Biology, University of North Carolina at Chapel Hill, 27599-3280, USA. rybczy@bio.unc.edu
authors.forename: Robert
authors.initials: R
authors.lastname: Rybczynski
authors.forename: Lawrence I
authors.initials: LI
authors.lastname: Gilbert
mesh_terms: D000818:Animals; D020013:Calcium Signaling; D026461:Ecdysteroids / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D007301:Insect Hormones / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism; D018402:Manduca / Q000378:metabolism / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D018978:Molting / Q000502:physiology*; D009479:Neuropeptides / Q000378:metabolism; D054799:Phospholipase C beta; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism* / Q000502:physiology; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D015398:Signal Transduction; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D026461:Ecdysteroids; D007301:Insect Hormones; D007527:Isoenzymes; D009479:Neuropeptides; D043562:Receptors, G-Protein-Coupled; C009089:prothoracicotropic hormone; D011493:Protein Kinase C; D048049:Extracellular Signal-Regulated MAP Kinases; D020928:Mitogen-Activated Protein Kinases; D010738:Type C Phospholipases; D054799:Phospholipase C beta