Effects of lipid rafts on signal transmembrane transduction mediated by c-Met / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To study the effects of lipid rafts on cell signal transmembrane transduction mediated by c-Met.</p><p><b>METHODS</b>After HepG2Cells were treated with MbCD to disrupt the lipid rafts and were treated with artificial recombination hepatocyte growth factor to activate c-Met, the activities of PLCr1/PKC, PI3K/Akt and MAPK signaling pathways in HepG2 cells were analyzed using Western blot.</p><p><b>RESULTS</b>(1) After disruption of lipid rafts with MbCD, phosphorylation of PLCr1 decreased by 35% (P = 0.022); the content of PLCr in the cytoplasm increased by 1.75 fold (P = 0.017); PLCr1 conjugated with membrane decreased by 30% (P = 0.037). (2) The content of PKB in the cytosol decreased by 38% (P = 0.028), and the phosphorylation level of PKB conjugated with membrane decreased by 14% (P = 0.041). At the same time, PDK translocation from cytosol to the plasma membrane and its activation were inhibited by treatment with MbCD. (3) Treatment with MbCD had no significant effect on ErK/MAPK, p38/MAPK and JNK/MAPK signaling pathways.</p><p><b>CONCLUSION</b>Disruption of lipid rafts with MbCD inhibits the activation of PLCr1/PKC and PI3K/PKB signaling pathways by HGF/cMet, but has no effect on MAPK signaling pathway.</p>

Overexpression of PEMT2 inhibits the phosphorylation and translocation of PLC gamma 1 / 中华肝脏病杂志

<p><b>OBJECTIVES</b>To explore the mechanism of CBRH-7919 cell proliferation inhibition by transfecting phosphatidylethanolamine N-methyltransferase 2 gene (PEMT2).</p><p><b>METHODS</b>The effects of PEMT2 transfection on phosphorylation and translocation from cytosol to plasma membrane of PLC gamma 1 in cells were studied using SDS-PAGE and Western blot techniques. The phosphorylation and activity of c-Met were determined.</p><p><b>RESULTS</b>After transfection of pemt2, the PLC gamma 1 and phosphorylated PLC gamma 1 conjugated with plasma membrane were decreased by 45% and 27% of that of control cells respectively, and the phosphorylated c-Met was decreased to 32% of that of control cells.</p><p><b>CONCLUSION</b>Transfection of phosphatidylethanolamine N-methyltransferase 2 gene can inhibit the phosphorylation and translocation from cytosol to plasma membrane of PLC gamma 1 in cells. At the same time, the autophosphorylation of c-Met was decreased, which suggests that transfection of phosphatidylethanolamine N-methyltransferase 2 gene can downregulate the c-Met/PLC gamma 1 signaling pathway in CBRH-7919 cells.</p>

Effects of overexpression of PEMT2 on expression and translocation of different PKC isoforms in rat hepatoma cells / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To explore the mechanism of cell proliferation inhibition by transfecting phosphatidylethanolamine N-methyltransferase 2 gene (PEMT2).</p><p><b>METHODS</b>The expression and translocation of different isoforms of protein kinase C (PKC) in cells were observed with immunocytochemistry and Western blot techniques. The content of diacylglycerol (DAG) was analyzed with high performance thin layer chromatography (HPTLC) technique.</p><p><b>RESULTS</b>Transfection of PEMT2 can inhibit the expression of cPKC alpha, but obviously promotes the expression and translocation from cytosol to plasma membrane of cPKC beta2. At the same time, the content of DAG was decreased in the transfected cells. Expression and translocation of other PKC isoforms were not changed by PEMT2 transfection.</p><p><b>CONCLUSION</b>Effects of overexpression of PEMT2 on the expression and translocation of different PKC isoforms might be related to the mechanism of cell proliferation inhibition and apoptosis induced by transfecting PEMT2.</p>