Search results for "protein kinase C"
showing 10 items of 180 documents
Inhibition of astroglial cell proliferation by alcohols: interference with the protein kinase C-phospholipase D signaling pathway.
2000
Abstract Ethanol inhibits astroglial cell proliferation, an effect that may contribute to the development of alcoholic embryopathy in humans. In the present study, we investigated inhibitory effects of ethanol and butanol isomers (1-, 2- and t -butanol) on astroglial cell proliferation induced by the strongly mitogenic phorbol ester, 4s-phorbol-12α,13s-dibutyrate (PDB). 4s-Phorbol-12α,13s-dibutyrate (PDB) induced a 10-fold increase of [3H]thymidine incorporation in cortical astrocytes prepared from newborn rats (EC 50 : 70 nM) which was blocked by Ro 31-8220, a cell-permeable protein kinase C (PKC) inhibitor. Ethanol blocked PDB-induced astroglial proliferation in a concentration-dependent …
Inhibitory effect of nonviable preparations from human immunodeficiency virus 1 on inositol phospholipid metabolism
1989
Previously it was established [Pahwa, S., Pahwa, R., Saxinger, C., Gallo, R. C. & Good, R. A. (1985) Proc. Natl Acad. Sci. USA 82, 8198] that nonviable preparations of human immunodeficiency virus 1 (HIV-1) abolish the proliferative response of human lymphocytes to phytohemagglutinin A. Now we describe that this effect might be, at least partially, due to an impairment of the function of phospholipase C. It was found that addition of HIV-1 preparation to lymphocytes diminished the stimulation of phosphatidylinositol phosphorylation caused by phytohemagglutinin A. Moreover, this preparation completely abolished the phytohemagglutinin-A-stimulated release of inositol trisphosphate and prevent…
Docosahexaenoic Acid Induces Increases in [Ca2+]ivia Inositol 1,4,5-Triphosphate Production and Activates Protein Kinase Cγ and -δ via Phosphatidylse…
2007
We investigated, in monocytic leukemia U937 cells, the effects of docosahexaenoic acid (DHA; 22:6 n-3) on calcium signaling and determined the implication of phospholipase C (PLC) and protein kinase C (PKC) in this pathway. DHA induced dose-dependent increases in [Ca2+]i, which were contributed by intracellular pool, via the production of inositol-1,4,5-triphosphate (IP3) and store-operated Ca2+ (SOC) influx, via opening of Ca2+ release-activated Ca2+ (CRAC) channels. Chemical inhibition of PLC, PKCgamma, and PKCdelta, but not of PKCbeta I/II, PKCalpha, or PKCbetaI, significantly diminished DHA-induced increases in [Ca2+]i. In vitro PKC assays revealed that DHA induced a approximately 2-fol…
Signal transduction pathways involved in the mechanical responses to protease-activated receptors in rat colon.
2002
Recording simultaneously in vitro the changes of endoluminal pressure (index of circular muscle activity) and isometric tension (index of longitudinal muscle activity), we examined the mechanisms responsible for the apamin-sensitive relaxant and contractile responses induced by protease-activated receptor (PAR)-1 and PAR-2 activating peptides, SFLLRN-NH2 and SLIGRL-NH2, respectively, in rat colon. In the circular muscle, the inhibitory effects of SFLLRN-NH2 and SLIGRL-NH2 were significantly reduced by ryanodine, an inhibitor of Ca2+ release from the sarcoplasmic reticulum, but unaffected by 1-[6-[[17beta-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U73122), a phosph…
Chronic exposure to ammonia induces isoform-selective alterations in the intracellular distribution and NMDA receptor-mediated translocation of prote…
2004
Hyperammonemia is responsible for most neurological alterations in patients with hepatic encephalopathy by mechanisms that remain unclear. Hyperammonemia alters phosphorylation of neuronal protein kinase C (PKC) substrates and impairs NMDA receptor-associated signal transduction. The aim of this work was to analyse the effects of hyperammonemia on the amount and intracellular distribution of PKC isoforms and on translocation of each isoform induced by NMDA receptor activation in cerebellar neurons. Chronic hyperammonemia alters differentially the intracellular distribution of PKC isoforms. The amount of all isoforms (except PKC zeta) was reduced (17-50%) in the particulate fraction. The con…
Rottlerin induces a transformed phenotype in human keratinocytes.
2001
PKCdelta plays a fundamental role in cell cycle control. Consistent with its proposed tumour suppressor function, ras transfection of the human keratinocyte cell line HaCaT results in a loss of PKCdelta expression mediated by TGFalpha (Exp. Cell Res., 219, 299, 1995). To get more insight into the role of PKCdelta in keratinocytes, we investigated the effects of Rottlerin, a specific inhibitor of protein kinase Cdelta, in HaCaT cells. After Rottlerin treatment, HaCaT cells lost their cobble-stone morphology and displayed a spindle-shaped, fibroblastic phenotype. Additionally, the establishment of cell-cell contacts was prevented. This was caused by an internalization of E-cadherin and beta-c…
STAT1 expression and activation is increased in lesional psoriatic skin
2013
Summary Background The JAK (Janus kinase)/STAT (signal transducer and activator of transcription) signalling pathway is known to play an important role in many cellular processes including inflammation. The activation of STAT1 is dependent on tyrosine 701 and serine 727 phosphorylation, which leads to the formation of the STAT dimer and modulation of STAT1 activity, respectively. Objective To determine STAT1 expression and activation in psoriatic skin. Methods Biopsies were collected from patients with psoriasis. mRNA expression was evaluated by quantitative polymerase chain reaction, whereas the protein and phosphorylation level of STAT1 were evaluated by Western blotting. STAT1 localiz…
[Apoptosis of human leukemic cells induced by topoisomerase I and II inhibitors].
1996
International audience; Comparison between five human leukemic lines (BV173, HL60, U937, K562, KCL22) suggest that the main determinant of their sensitivity to topoisomerase I (camptothecin) and II (VP-16) inhibitors is their ability to regulate cell cycle progression in response to specific DNA damage, then to die through apoptosis: the more the cells inhibit cell cycle progression, the less sensitive they are. The final pathway of apoptosis induction involves a cytoplasmic signal, active at neutral pH, needing magnesium, sensitive to various protease inhibitors and activated directly by staurosporine. Modulators of intracellular signaling (calcium chelators, calmodulin inhibitors, PKC mod…
eNOS S-nitrosylates β-actin on Cys374 and regulates PKC-θ at the immune synapse by impairing actin binding to profilin-1.
2017
The actin cytoskeleton coordinates the organization of signaling microclusters at the immune synapse (IS); however, the mechanisms involved remain poorly understood. We show here that nitric oxide (NO) generated by endothelial nitric oxide synthase (eNOS) controls the coalescence of protein kinase C-¿ (PKC-¿) at the central supramolecular activation cluster (c-SMAC) of the IS. eNOS translocated with the Golgi to the IS and partially colocalized with F-actin around the c-SMAC. This resulted in reduced actin polymerization and centripetal retrograde flow of ß-actin and PKC-¿ from the lamellipodium-like distal (d)-SMAC, promoting PKC-¿ activation. Furthermore, eNOS-derived NO S-nitrosylated ß-…
Anti-inflammatory activity of berenjenol and related compounds.
2008
Berenjenol ( 1), isolated from OXANDRA cf. XYLOPIOIDES (Annonaceae), was tested on two different experimental models of inflammation. The compound showed anti-inflammatory activity in the test of acute mouse ear edema induced by TPA (54 % inhibition, 1 μmol/ear) as well as in the test of subchronic inflammation induced by repeated application of TPA (57 % inhibition, 7 × 1 μmol/ear). Moreover, while it reduced the expression of both COX-2 (65 % inhibition at 50 μM) and iNOS (80 % inhibition at 50 μM), it was not active against TNF- α and IL-1 β in murine macrophages (RAW 264.7) stimulated with LPS. Structural modification of 1 gave two derivatives, berenjenol acetate ( 2) and 3-oxo-berenjen…