scholarly journals Second-messenger control of catecholamine release from PC12 cells. Role of muscarinic receptors and nerve-growth-factor-induced cell differentiation

1988 ◽  
Vol 255 (3) ◽  
pp. 761-768 ◽  
Author(s):  
J Meldolesi ◽  
G Gatti ◽  
A Ambrosini ◽  
T Pozzan ◽  
E W Westhead
Keyword(s):  
Protein Kinase C ◽  
Nerve Growth Factor ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Pc12 Cells ◽  
Neurotransmitter Release ◽  
Phorbol Esters ◽  
Kinase C ◽  
High K

The role of various intracellular signals and of their possible interactions in the control of neurotransmitter release was investigated in PC12 cells. To this purpose, agents that affect primarily the cytosolic concentration of Ca2+, [Ca2+]i (ionomycin, high K+), agents that affect cyclic AMP concentrations (forskolin; the adenosine analogue phenylisopropyladenosine; clonidine) and activators of protein kinase C (phorbol esters) were applied alone or in combination to either growing chromaffin-like PC12-cells, or to neuron-like PC12+ cells differentiated by treatment with NGF (nerve growth factor). In addition, the release effects of muscarinic-receptor stimulation (which causes increase in [Ca2+]i, activation of protein kinase C and decrease in cyclic AMP) were investigated. Two techniques were employed to measure catecholamine release: static incubation of [3H]dopamine-loaded cells, and perfusion incubation of unlabelled cells coupled to highly sensitive electrochemical detection of released catecholamines. The results obtained demonstrate that: (1) release from PC12 cells can be elicited by both raising [Ca2+]i and activating protein kinases (protein kinase C and, although to a much smaller extent, cyclic AMP-dependent protein kinase); and (2) these various control pathways interact extensively. Activation of muscarinic receptors by carbachol induced appreciable release responses, which appeared to be due to a synergistic interplay between [Ca2+]i and protein kinase C activation. The muscarinic-induced release responses tended to become inactivated rapidly, possibly by feedback desensitization of the receptor mediated by protein kinase C. Muscarinic inactivation was prevented (or reversed) by agents that increase, and accelerated by agents that decrease, cyclic AMP. Agents that stimulate release primarily through the Ca2+ pathway (ionomycin and high K+) were found to be equipotent in both PC12- and PC12+ cells, whereas the protein kinase C activator 12-O-tetradecanoyl-phorbol 13-acetate was approx. 10-fold less potent in PC12+ cells, when administered either alone or in combination with ionomycin. In contrast, the cell binding of phorbol esters was not greatly modified by NGF treatment. Thus control of neurotransmitter release from PC12 cells is changed by differentiation, with a diminished role of the mechanism mediated by protein kinase C.

scholarly journals p21WAF1 expression by an activator of protein kinase C is regulated mainly at the post-transcriptional level in cells lacking p53: important role of RNA stabilization

1999 ◽  
Vol 337 (3) ◽  
pp. 607-616 ◽  
Author(s):  
Makoto AKASHI ◽  
Yoshiaki OSAWA ◽  
H. Phillip KOEFFLER ◽  
Misao HACHIYA
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phorbol Esters ◽  
P53 Protein ◽  
Mitogen Activated Protein Kinase ◽  
Luciferase Reporter ◽  
Transcriptional Level ◽  
Kinase C ◽  
In Cells

p21WAF1 inhibits cyclin–cyclin-dependent kinase (Cdk) complexes, causing cell cycle arrest. p21WAF1 contains p53-binding sites in its promoter and expression of p21WAF1 is induced by functional p53. In the present work, we have studied the role of protein kinase C (PKC) in the induction of p21WAF1 and show that induction of p21WAF1 expression can occur by activation of PKC in cells having no p53. Human ovarian carcinoma cells, SKOV-3, lack p53 protein and PMA, a potent activator of PKC, did not induce p53. PMA increased the expression of p21WAF1 mRNA both in these cells and in other cells which do not contain p53 (THP-1 and U937). Treatment of human embryonic fibroblasts, WI38, with PMA also induced the accumulation of p21WAF1 without affecting p53 levels. However, PMA did not increase levels of p21WAF1 mRNA in cells where either the PKC or the mitogen-activated protein kinase pathway was blocked. Furthermore, treatment of cells with various phorbol ester derivatives which activate PKC resulted in the induction of p21WAF1 in SKOV-3 cells. In contrast, phorbol esters which do not activate PKC failed to induce p21WAF1 expression. PMA increased the transcriptional rate of p21WAF1 and activated the transcription of a luciferase reporter gene, controlled by the p21 promoter, in SKOV-3 cells with or without a p53 consensus-binding sequence. By contrast, PMA markedly stabilized p21WAF1 mRNA; the half-life (t1/2) of p21WAF1 in PMA-treated cells was > 8 h compared with < 1 h in untreated cells. These findings provide evidence that the PKC pathway induces expression of p21WAF1 independently of p53. Our present study also suggests that the accumulation of p21WAF1 transcripts by PMA occurs mainly at post-transcriptional level.

Differential effects of intracellular calcium elevating agents on adrenergic-stimulated cyclic nucleotide and melatonin synthesis in rat pinealocytes

1992 ◽  
Vol 70 (9) ◽  
pp. 1254-1260 ◽  
Author(s):  
Anthony K. Ho ◽  
Joshua Cheng ◽  
Marc Girard
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Intracellular Calcium ◽  
Cyclic Nucleotide ◽  
Melatonin Synthesis ◽  
Kinase C ◽  
Mechanism Of Inhibition ◽  
Intracellular Ca

In this study, the role of elevation of intracellular Ca2+ and activation of protein kinase C on adrenergic-stimulated cyclic nucleotide accumulation and melatonin synthesis in rat pinealocytes was investigated. It was found that whereas KCl, ionomycin, and ouabain, three Ca2+-elevating agents, had a potentiating effect on adrenergic-stimulated cylic AMP response, their effects on melatonin synthesis were inhibitory. Similar inhibition was also observed when dibutyryl cyclic AMP was used to stimulate melatonin synthesis. By determining intracellular Ca2+ directly, it was found that the enhancing effects of these agents on the cyclic AMP response but not their inhibitory effects on melatonin synthesis paralleled their abilities to elevate intracellular Ca2+. In comparison, activation of protein kinase C significantly enhanced the adrenergic-stimulated cyclic AMP response and, to a lesser degree, the adrenergic-stimulated N-acetyltransferase and melatonin levels. These results indicate that (i) Ca2+-elevating agents have opposite effects on adrenergic-stimulated cyclic AMP and melatonin production; (ii) a post cyclic AMP event of importance to melatonin synthesis is inhibited by these agents; and (iii) the mechanism of inhibition may not be directly related to their effect on intracellular Ca2+.Key words: intracellular calcium, protein kinase C, melatonin, pineal gland.

Nerve growth factor enhances the level of the protein kinase C substrate B-50 in pheochromocytoma PC12 cells

1986 ◽  
Vol 139 (2) ◽  
pp. 644-651 ◽  
Author(s):  
C.O.M. Van Hooff ◽  
P.N.E. De Graan ◽  
J. Boonstra ◽  
A.B. Oestreicher ◽  
M.H. Schmidt-Michels ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Protein Kinase ◽  
Pc12 Cells ◽  
Nerve Growth ◽  
Kinase C ◽  
Pheochromocytoma Pc12 ◽  
Pheochromocytoma Pc12 Cells

Protein kinase C regulates endocytosis and recycling of E-cadherin

2002 ◽  
Vol 283 (2) ◽  
pp. C489-C499 ◽  
Author(s):  
Tam Luan Le ◽  
Shannon R. Joseph ◽  
Alpha S. Yap ◽  
Jennifer L. Stow
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phorbol Esters ◽  
Recycling Endosomes ◽  
Kinase C ◽  
Pkc Isozymes ◽  
Pkc Activation ◽  
Darby Canine Kidney ◽  
E Cadherin

E-cadherin is a major component of adherens junctions in epithelial cells. We showed previously that a pool of cell surface E-cadherin is constitutively internalized and recycled back to the surface. In the present study, we investigated the potential role of protein kinase C (PKC) in regulating the trafficking of surface E-cadherin in Madin-Darby canine kidney cells. Using surface biotinylation and immunofluorescence, we found that treatment of cells with phorbol esters increased the rate of endocytosis of E-cadherin, resulting in accumulation of E-cadherin in apically localized early or recycling endosomes. The recycling of E-cadherin back to the surface was also decreased in the presence of phorbol esters. Phorbol ester-induced endocytosis of E-cadherin was blocked by specific inhibitors, implicating novel PKC isozymes, such as PKC-ε in this pathway. PKC activation led to changes in the actin cytoskeleton facilitating E-cadherin endocytosis. Depolymerization of actin increased endocytosis of E-cadherin, whereas the PKC-induced uptake of E-cadherin was blocked by the actin stabilizer jasplakinolide. Our findings show that PKC regulates vital steps of E-cadherin trafficking, its endocytosis, and its recycling.

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