Protein kinase C-mediated phospholipase A2 activation, platelet-activating factor generation and prostacyclin release in spontaneously beating rat cardiomyocytes

Church, Dennis J.; Braconi, Simone; Vallotton, Michel B.; Lang, Ursula

doi:10.1042/bj2900477

Cited by 60 publications

(43 citation statements)

References 39 publications

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“…The most common subcellular localizations of the activated PKC isoforms include the plasma membrane and the nucleus. The cellular distribution of SPKC has remained unclear because the experimental approach used to address this issue has been limited to subcellular fractionation, a technique with poor reproducibility and unclear results [16][17][18][19][20][21][22][23][24][25][26][27]. Confocal microscopy resolves the controversy of LPKC localization by the use of intact fixed cells instead of subcellular fractions.…”

Section: Discussionmentioning

confidence: 99%

Physical association and functional relationship between protein kinase Cζ and the actin cytoskeleton

et al. 1995

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Protein kinase C (PKC) was initially identified as a serine/threonine protein kinase dependent on calcium and phospholipids and shown to be involved in intracellular signaling pathways. PKC isoforms have been classified into four groups: Ca(2+)-dependent conventional PKC alpha, beta I, beta II, gamma; Ca(2+)-independent, novel PKC delta, epsilon, eta, phi; atypical PKC zeta, lambda, iota which are not activated by Ca2+ or diacylglycerol, and the recently discovered PKCmu. We reported that activation of the zeta PKC isoform is an important step in interleukin-2 (IL-2)-mediated proliferation (Gómez, J., Pitton, C., García, A., Martínez, A., Silva, A. and Rebollo, A., Exp. Cell Res. 1995. 218: 105.). zeta PKC is also required for mitogenic activation of fibroblasts and for the maturation pathway activated by insulin and Ras. Contradictory results have been reported regarding the subcellular redistribution of zeta PKC upon activation. We report here, using confocal microscopy, that IL-2 induces expression, translocation and association of zeta PKC to a structure coincident with the actin cytoskeleton. Furthermore, we show that zeta PKC has a role in maintaining the integrity of the actin cytoskeletal structure in IL-2-stimulated cells. On the contrary, zeta PKC is not involved in the actin cytoskeleton organization when cells are maintained in IL-4, confirming our previous results showing that IL-4-induced signal transduction is PKC independent.

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Section: Discussionmentioning

confidence: 99%

Physical association and functional relationship between protein kinase Cζ and the actin cytoskeleton

et al. 1995

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“…34,35 PLA 2 involvement was assessed using 3 g/mL melittin (PLA 2 activator) (Bio-Mol, Plymouth Meeting, PA) or 10 M quinacrine (PLA 2 inhibitor) (Bio-Mol), as described previously. 36,37 Cell number and alkaline phosphatasespecific activity were determined after 24 h; PKC-specific activity was measured after 9 min and 24 h of treatment.…”

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 99%

Surface roughness modulates the response of MG63 osteoblast-like cells to 1,25-(OH)2D3 through regulation of phospholipase A2 activity and activation of protein kinase A

Lohmann

Sagun

Sylvia

et al. 1999

J. Biomed. Mater. Res.

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Implant surface roughness influences osteoblast proliferation, differentiation, and local factor production. Moreover, the responsiveness of osteoblasts to systemic hormones such as 1, 25-(OH)(2)D(3) is altered by the effects of surface roughness; on the roughest Ti surfaces the effects of roughness and 1, 25-(OH)(2)D(3) are synergistic. Prostaglandin E(2) (PGE(2)) appears to be involved in mediating the effects of surface roughness on the cells, as well as in the response to 1,25-(OH)(2)D(3). However, it is not yet known through which signaling pathways surface roughness exerts its effects on the response of osteoblasts to 1, 25-(OH)(2)D(3). The present study examined the potential role of protein kinase A (PKA), phospholipase A(2)(PLA(2)), and protein kinase C (PKC) in this process. MG63 osteoblast-like human osteosarcoma cells were cultured on cpTi disks with R(a) values of 0. 54 microm (PT), 4.14 microm (SLA), or 4.92 microm (TPS). PKA was inhibited by adding H8 to the cultures; similarly, PLA(2) was inhibited with quinacrine or activated with melittin, and PKC was inhibited with chelerythrine. Inhibitors or activators were included in the culture media through the entire culture period or for the last 24 h of culture. In addition, cultures were treated for 24 h with inhibitors or activators in the presence of 1,25-(OH)(2)D(3). The effects on cell number and alkaline phosphatase specific activity were determined after 24 h; PKC activity was determined after 9 min and at 24 h. Cell number was reduced on rough surfaces, and alkaline phosphatase activity was increased. 1,25-(OH)(2)D(3) had a synergistic effect with surface roughness on alkaline phosphatase. However, neither surface roughness nor 1,25-(OH)(2)D(3) had an effect on PKC. H8 treatment for 24 h inhibited cell number and alkaline phosphatase on all surfaces; however, when it was present throughout the culture period, the PKA inhibitor had no effect on cell number, but decreased alkaline phosphatase-specific activity. H8 reduced the 1,25-(OH)(2)D(3)-mediated effect on cell number and alkaline phosphatase. Quinacrine inhibited cell proliferation and alkaline phosphatase on all surfaces and further reduced the 1,25-(OH)(2)D(3)-dependent decreases in both parameters. Melittin had no effect when applied for 24 h and did not modify the 1,25-(OH)(2)D(3) effect; however, when present throughout the culture period, it caused a decrease in proliferation and an increase in enzyme activity. Chelerythrine, the PKC inhibitor, only inhibited cell proliferation when it was present throughout the entire culture period. However, it decreased alkaline phosphatase in cultures treated for 24 h, but increased enzyme activity when it was present for the entire culture period. The results indicate that surface roughness and 1,25-(OH)(2)D(3) both mediate their effects through PLA(2) which catalyzes the rate-limiting step in PGE(2) production. Further downstream, PGE(2) activates PKA. Surface roughness-dependent effects are also mediated through PKC, but only after the cells ha...

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“…However, the precise identity of the PKC species that mediate these functions remains uncertain, since several PKC isoforms are coexpressed by cardiac myocytes. For example, neonatal rat ventricular myocytes express at least one conventional PKC isoform (PKC ␣ ) which is activated by calcium, phosphatidylserine, and diacylglycerol (DAG)/phorbol esters, two novel PKC isoforms (PKC ␦ and PKC ⑀ ) which are activated by phosphatidylserine and DAG/phorbol esters (but do not require calcium for maximal enzyme activation), and one atypical PKC isoform (recently identified as PKC , rather than PKC [3]) which is activated by phosphatidylserine (but not by calcium or DAG/ phorbol esters [4][5][6][7][8][9]). Apart from differences in their cofactor requirements for enzymatic activation, these PKC isoforms target to distinct subcellular loci (including the perinuclear membrane, cytoskeleton, and myofibrillar apparatus [6]) and are presumed to differ in their in vivo substrate specificity.…”

Section: Introductionmentioning

confidence: 99%

Hypoxia alters the subcellular distribution of protein kinase C isoforms in neonatal rat ventricular myocytes.

Goldberg

Zhang²,

Steinberg³

1997

J. Clin. Invest.

130

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Cardiac myocytes coexpress multiple protein kinase C (PKC) isoforms which likely play distinct roles in signaling pathways leading to changes in contractility, hypertrophy, and ischemic preconditioning. Although PKC has been reported to be activated during myocardial ischemia, the effect of ischemia/hypoxia on individual PKC isoforms has not been determined. This study examines the effect of hypoxia on the subcellular distribution of individual PKC isoforms in cultured neonatal rat ventricular myocytes.

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Protein kinase C-mediated phospholipase A2 activation, platelet-activating factor generation and prostacyclin release in spontaneously beating rat cardiomyocytes

Cited by 60 publications

References 39 publications

Physical association and functional relationship between protein kinase Cζ and the actin cytoskeleton

Physical association and functional relationship between protein kinase Cζ and the actin cytoskeleton

Surface roughness modulates the response of MG63 osteoblast-like cells to 1,25-(OH)2D3 through regulation of phospholipase A2 activity and activation of protein kinase A

Hypoxia alters the subcellular distribution of protein kinase C isoforms in neonatal rat ventricular myocytes.

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