Peptidergic Modulation of an Insect Na+ Current: Role of Protein Kinase A and Protein Kinase C

2001 ◽  
Vol 85 (1) ◽  
pp. 374-383 ◽  
Author(s):  
Dieter Wicher
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Time Constant ◽  
Periplaneta Americana ◽  
Dependent Manner ◽  
Patch Clamp Technique ◽  
Concentration Dependent Manner ◽  
Kinase C ◽  
Kinase A

The modulation of voltage-gated Na+ currents in isolated somata of dorsal unpaired median (DUM) neurons of the cockroach Periplaneta americana was investigated using the patch-clamp technique. The neuropeptide Neurohormone D (NHD), which belongs to the family of adipokinetic hormones, reversibly reduced the Na+ current in concentration-dependent manner (1 pM to 10 nM). At 10 nM, NHD caused an attenuation of the maximum of current-voltage ( I-V) relation for peak currents by 23 ± 6%. An analysis of NHD action on current kinetics in terms of the Hodgkin-Huxley formalism revealed that NHD reduces the time constant of inactivation, whereas steady-state activation and inactivation as well as the time constant of activation were not affected. In addition, NHD prolonged the recovery from inactivation. The cAMP analogue 8-bromo-cAMP, forskolin, and the catalytic subunit of protein kinase A mimicked the action of NHD. Furthermore, preincubation of cells with the protein kinase A inhibitor KT 5720 abolished the action of NHD. Thus NHD seems to modify the Na+ current via channel phosphorylation by protein kinase A. Activation of protein kinase C by oleoylacetylglycerol (OAG) also reduced the Na+ current, but it did not occlude the action of NHD. On the other hand, inhibition of protein kinase C by chelerythrine or Gö 6976 did not essentially impair the NHD effects.

Inhibition of PAH transport by parathyroid hormone in OK cells: involvement of protein kinase C pathway

1997 ◽  
Vol 273 (5) ◽  
pp. F674-F679 ◽  
Author(s):  
Junya Nagai ◽  
Ikuko Yano ◽  
Yukiya Hashimoto ◽  
Mikihisa Takano ◽  
Ken-Ichi Inui
Keyword(s):  
Protein Kinase C ◽  
Parathyroid Hormone ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Regulatory Control ◽  
Dependent Manner ◽  
Transcellular Transport ◽  
Ok Cells ◽  
Kinase C ◽  
Kinase A

We have previously shown that the p-aminohippurate (PAH) transport system in OK kidney epithelial cell line is under the regulatory control of protein kinase C. Parathyroid hormone (PTH) could activate protein kinase C, as well as protein kinase A, in OK cells. In the present study, the effect of PTH on PAH transport was studied in OK cells. PTH inhibited the transcellular transport of PAH from the basal to the apical side, as well as the accumulation of PAH in OK cells. Basolateral PAH uptake was inhibited by PTH in a dose- and time-dependent manner. Protein kinase A activators did not affect the transcellular transport or the accumulation of PAH. The PTH-induced inhibition of the accumulation of PAH was blocked by a protein kinase C inhibitor staurosporine. These results suggest that PTH inhibits the PAH transport in OK cells and that the messenger system mediated by protein kinase C, not protein kinase A, plays an important role in the regulation of PAH transport by PTH.

Ca2+-, phorbol ester-, and cAMP-stimulated enzyme secretion from permeabilized rat pancreatic acini

1986 ◽  
Vol 250 (5) ◽  
pp. G698-G708 ◽  
Author(s):  
T. Kimura ◽  
K. Imamura ◽  
L. Eckhardt ◽  
I. Schulz
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Protein Release ◽  
Enzyme Secretion ◽  
Dependent Manner ◽  
Intact Cells ◽  
Pancreatic Acini ◽  
Kinase C ◽  
Kinase A

Enzyme secretion from the exocrine pancreas is stimulated by receptor-activated breakdown of phosphatidylinositol 4,5-bisphosphate and consequent rise of both inositol 1,4,5-trisphosphate (IP3) and diacylglycerol, which leads to Ca2+ release and to activation of protein kinase C, respectively. Another way involves receptor-mediated stimulation of adenylate cyclase and consequent rise of cAMP and activation of protein kinase A. In the present work we have studied direct stimulation, inhibition, and mutual interaction of these pathways on enzyme secretion from isolated rat pancreatic acini that had been permeabilized by treatment with saponin or digitonin. The data were compared with those obtained in isolated intact acini. The data show that with increasing free Ca2+ concentrations greater than 10(-6) M protein release increases in "leaky" but not in "intact" cells and is maximal at approximately 10(-3) M, increasing about twofold compared with that in the absence of Ca2+. In the presence of the acetylcholine analogue carbachol, this effect of Ca2+ is enhanced by about threefold in leaky cells and is also present in intact cells to a similar extent. cAMP and its analogues, dibutyryl cAMP (dbcAMP) and 8-bromo-cAMP stimulate protein release by about twofold in the presence of Ca2+ in leaky cells. In intact acini cAMP has no effect, and cAMP analogues stimulate enzyme secretion by about twofold in some but not all experiments. Similarly, forskolin, an activator of adenylate cyclases and inhibitors of cyclic nucleotide-dependent phosphodiesterases, such as 3-isobutyl-1-methylxanthine (IBMX) and R0 201724, stimulate protein release in permeabilized acini. The Ca2+-binding protein calmodulin has no effect on enzyme secretion, whereas the calmodulin antagonist trifluoperazine dihydrochloride stimulates protein release in leaky but not in intact acini. The activator of protein kinase C, 12-O-tetradecanoylphorbol 13-acetate (TPA) stimulates protein release in a Ca2+-dependent manner and enhances cAMP-induced secretion. The effects of carbachol, TPA, cAMP, and a combination of both TPA and cAMP are inhibited by the polyamine spermine in permeabilized cells. Spermine has no effect on carbachol-induced enzyme secretion in intact cells. The data suggest that enzyme secretion from pancreatic acinar cells is mediated by cAMP protein kinase A and by Ca2+ phospholipid protein kinase C in a Ca2+-dependent way and that interaction occurs between both pathways.

Phosphorylation of NADPH oxidase activator 1 (NOXA1) on serine 282 by MAP kinases and on serine 172 by protein kinase C and protein kinase A prevents NOX1 hyperactivation

2010 ◽  
Vol 24 (6) ◽  
pp. 2077-2092 ◽  
Author(s):  
Yolande Kroviarski ◽  
Maya Debbabi ◽  
Rafik Bachoual ◽  
Axel Pe´rianin ◽  
Marie‐Anne Gougerot‐Pocidalo ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Nadph Oxidase ◽  
Protein Kinase A ◽  
Map Kinases ◽  
Kinase C ◽  
Kinase A

scholarly journals Pituitary adenylate cyclase activating polypeptide as a novel hypophysiotropic factor in fish

2000 ◽  
Vol 78 (3) ◽  
pp. 329-343 ◽  
Author(s):  
Anderson OL Wong ◽  
Wen Sheng Li ◽  
Eric KY Lee ◽  
Mei Yee Leung ◽  
Lai Yin Tse ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Adenylate Cyclase ◽  
Protein Kinase A ◽  
Anterior Pituitary ◽  
Kinase C ◽  
Pituitary Adenylate Cyclase ◽  
Pacap Receptors ◽  
Kinase A

Pituitary adenylate cyclase activating polypeptide (PACAP) is a novel member of the secretin-glucagon peptide family. In mammals, this peptide has been located in a wide range of tissues and is involved in a variety of biological functions. In lower vertebrates, especially fish, increasing evidence suggests that PACAP may function as a hypophysiotropic factor regulating pituitary hormone secretion. PACAP has been identified in the brain-pituitary axis of representative fish species. The molecular structure of fish PACAP is highly homologous to mammalian PACAP. The prepro-PACAP in fish, however, is distinct from that of mammals as it also contains the sequence of fish GHRH. In teleosts, the anterior pituitary is under direct innervation of the hypothalamus and PACAP nerve fibers have been identified in the pars distalis. Using the goldfish as a fish model, mRNA transcripts of PACAP receptors, namely the PAC1 and VPAC1 receptors, have been identified in the pituitary as well as in various brain areas. Consistent with the pituitary expression of PACAP receptors, PACAP analogs are effective in stimulating growth hormone (GH) and gonadotropin (GTH)-II secretion in the goldfish both in vivo and in vitro. The GH-releasing action of PACAP is mediated via pituitary PAC1 receptors coupled to the adenylate cyclase-cAMP-protein kinase A and phospholipase C-IP3-protein kinase C pathways. Subsequent stimulation of Ca2+ entry through voltage-sensitive Ca2+ channels followed by activation of Ca2+-calmodulin protein kinase II is likely the downstream mechanism mediating PACAP-stimulated GH release in goldfish. Although the PACAP receptor subtype(s) and the associated post-receptor signaling events responsible for PACAP-stimulated GTH-II release have not been characterized in goldfish, these findings support the hypothesis that PACAP is produced in the hypothalamus and delivered to the anterior pituitary to regulate GH and GTH-II release in fish.Key words: PACAP, VIP, PAC1 receptor, VPAC1 receptor, VPAC2 receptor, growth hormone, gonadotropin-II, cAMP, protein kinase A, protein kinase C, calcium, pituitary cells, goldfish, and teleost.

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