Role of intracellular calcium mobilization in the regulation of protein kinase C-mediated membrane processes

Nature ◽  
1985 ◽  
Vol 317 (6037) ◽  
pp. 549-551 ◽  
Author(s):  
W. S. May ◽  
N. Sahyoun ◽  
M. Wolf ◽  
P. Cuatrecasas
1986 ◽  
Vol 12 (1) ◽  
pp. 37-51 ◽  
Author(s):  
Arthur R. Buckley ◽  
David W. Montgomery ◽  
Ruthann Kibler ◽  
Charles W. Putnam ◽  
Charles F. Zukoski ◽  
...  

1992 ◽  
Vol 70 (9) ◽  
pp. 1254-1260 ◽  
Author(s):  
Anthony K. Ho ◽  
Joshua Cheng ◽  
Marc Girard

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.


Glia ◽  
1995 ◽  
Vol 15 (2) ◽  
pp. 119-130 ◽  
Author(s):  
Danica B. Stanimirovic ◽  
Rita Ball ◽  
Geoff Mealing ◽  
Paul Morley ◽  
Jon P. Durkin

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2020-2020
Author(s):  
Yamini Bynagari ◽  
Parth Lakhani ◽  
Kamala Bhavaraju ◽  
Jianguo Jin ◽  
Mario C Rico ◽  
...  

Abstract Abstract 2020 Positive regulatory role of Protein Kinase C (PKC) isoforms in platelets have been extensively studied. However, negative regulatory roles of PKCs in platelets are poorly understood. In this study we investigated the mechanism by which PKCs negatively regulate ADP-induced thromboxane generation and identified PKC isoforms involved in this process. Pan PKC inhibition with GF109203X potentiated ADP-induced cPLA2 phosphorylation suggesting that PKCs negatively regulate thromboxane generation by regulating cPLA2 activation. Inhibition of PKCs potentiated ADP-induced ERK activation and intracellular calcium mobilization, two upstream signaling molecules of cPLA2.These data suggest that PKCs negatively regulate thromboxane by regulating ERK activation and calcium mobilization, which inturn regulate cPLA2 activation. Pan-PKC inhibition potentiated ADP-induced, P2Y1 receptor-mediated calcium mobilization in platelets independent of P2Y12-receptor. Pretreatment of platelets with GF109203X, a Pan PKC inhibitor, but not Go-6976, a classical PKC isoform inhibitor, potentiated ADP-induced thromboxane generation. Thus, we investigated the role of various novel class of PKC isoforms (nPKCs) in platelets. We have previously demonstrated that nPKC η, θ, δ positively regulates agonist-induced thromboxane generation in platelets. Thus, we investigated if the role of nPKC ε in ADP-induced thromboxane generation using PKC ε knockout mice (PKCε KO). ADP-induced thromboxane generation in PKC ε KO murine platelets was ten-fold higher than that of wild type platelets. Furthermore, PKC ε KO mice exhibited shorter times to occlusion in FeCl3-induced arterial injury model and shorter bleeding times in Tail bleeding experiments. We conclude that PKCε negatively regulates ADP-induced thromboxane generation in platelets and thereby offers protection against thrombosis. Disclosures: No relevant conflicts of interest to declare.


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