Antibodies against phospholipase C inhibit smooth muscle contraction induced by acetylcholine and histamine

Moraru, Ion I.; Popescu, L. M.; Vidulescu, Cristina; Tzigaret, Cezar

doi:10.1016/0014-2999(87)90483-3

Cited by 13 publications

(5 citation statements)

References 9 publications

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“…Similar results were reported by Fields et al [18] on the entry of another enveloped virus, the human immunodeficiency 1 virus, into CD4 positive cells. The effect of PKC inhibitors was not mimicked by inhibitory antibodies directed to cell-membrane phospholipases (PLC-PI, PLC-PC or PLA_,), although these antibodies decreased basal and agonist-induced production of DAG in living cells [15][16][17]. Noteworthy, PKC inhibitors also inhibited the Fcy-receptor mediated endocytosis in neutrophils, but in that case the antibodies were also inhibitory [6], suggesting that the routes for PKC activation are different for these two processes.…”

Section: Discussionmentioning

confidence: 93%

Effects of protein kinase C inhibitors on viral entry and infectivity

1991

FEBS Letters

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The protein kinase C inhibitor H-7 (2-20/aM) inhibited dose-dependently the infectivity of the vesicular stomatitis virus on cultured human fibroblasts. Electron microscopy showed that H-7 inhibited the viral entry. H-7 also inhibited the infectivity of four other enveloped viruses, herpes simplex I, turkey herpes, vaecinia and $indbis. Similar results were obtained using staurosporine (2.5 riM), tamoxifen (40/aM). phloretin (140/aM). or W-7 (40/aM). However, the infectivity of non-enveloped viruses (e.g. poliomyelitis I) was not inhibited by H-7. These results show that protein kinase C is critically involved in the infectivity of enveloped viruses, most probably at the level of viral entry (receptor-mediated endocytosis). MATERIALS AND METHODS CeUsConfluent monolayers of human embryo fibroblasts (HEF)or chicken embryo fibroblasts (CEF) were grown in Eagle's medium supplemented with 10% fetal calf serum. 2 mM glutamine, 100 U/ml penicillin and were used 3-4 days after seeding [8,9]. VirusesVesicular stomatitis virus (VSV) (Indiana strain), herpes simplex I virus (HSV-I) (Maclntyre strain), poliomyelitis virus I (Mahoney strain), vaccinia virus (Elstree strain) and Sindbis virus (Ar-339 strain)

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Section: Discussionmentioning

confidence: 93%

Effects of protein kinase C inhibitors on viral entry and infectivity

1991

FEBS Letters

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“…Both could lead to PKC activation [2,22]. Our results with specific anti-PLC and anti-PLA2 antibodies, which bind to and inhibit the cellmembrane enzymes [12,[14][15][16][17], suggest an important cooperative involvement of PLC and PLA2 activity in triggering endocytosis. The endocytosis inhibition induced by PLC and PLA2 blockade is probably due to the failure of subsequent PKC activation because this inhibition is reversed if the assay medium contains the direct PKC activator phorbol 12,13-dibutyrate.…”

Section: Discussionmentioning

confidence: 87%

“…The antibodies dose-dependently inhibit the respective enzymes in living cells [12,[14][15][16][17].…”

Section: Anti-phospholipase Antibodiesmentioning

confidence: 99%

Protein kinase C controls Fcγ receptor‐mediated endocytosis in human neutrophils

Moraru

Laky²,

Stãnescu³

et al. 1990

FEBS Letters

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The aim of this study is to clarify which signaling mechanism operates in Fc7 receptor-mediated endocytosis in human neutrophils. Endocytosis of immune complexes was inhibited by antibodies directed to cell membrane phospholipase C (PLC) and A 2 (PLA2) (maximal inhibition obtained was 57% and 28%, respectively), being almost abolished by these antibodies if used in combination (up to 91~ inhibition). The protein kinase C (PKC) activator, phorbol 12,13-dibutyrate, reversed this inhibitory effect. Four different PKC inhibitors (H-7, palmitoylcarnitine, sphingosine, and tamoxifen) produced a dose-dependent inhibition of endocytosis, up to over 80% in each case. H-8 (I-10/~M) which inhibits cyclic nucleotide protein kinases but not PKC had no effect upon endocytosis. It is concluded that Fc~, receptor-induced activation of PLC and PLA 2 triggers endocytosis by activation of PKC.

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“…These regions of homology could explain the results obtained with our polyclonal antibody. If so, one should expect cross-reactivity to occur on a large scale-which makes this anti-PLC antibody a useful tool in the investigation of PLC role or localization in various cells, as we have previously suggested (20,21). Additional proof was provided by cooperative research with Drs.…”

Section: Discussionmentioning

confidence: 88%

“…3.1.4.3.; Calbiochem, Frankfurt/Main) was obtained as previously described (20,21). The F(ab')2 fragment of the antibody molecule was prepared by pepsin digestion as follows: after incubation of the antibody for 24 hr at 37°C with pepsin (3 x crystallized; Serva 3.4.4.1.; 2500 E/mg) at an antibody/enzyme ratio of 10/1 in sodium acetate buffer 0.1 M, pH 4.5, the reaction was stopped by raising pH to 8.0.…”

Section: Antibodiesmentioning

confidence: 99%