title: [GRP75 overexpression inhibits apoptosis induced by glucose deprivation via Raf/Mek/Erk1/2 signaling pathway].
abstract: The purpose of the present study is to investigate whether glucose-regulated protein 75 (GRP75) overexpression inhibits apoptosis induced by glucose deprivation through Raf/Mek/Erk1/2 signaling pathway. After pretreatment with Mek-specific inhibitor U0126, GRP75 overexpressing PC12 cells were incubated in glucose-free DMEM medium for indicated time (6, 12 and 24 h). And DMSO-treated GRP75 overexpressing PC12 cells were applied as control. Western blot was used to determine the expression and phosphorylation level of Erk1/2. MTT assay was used to measure cell viability. Hoechst 33258 staining and flow cytometry using propidium iodide (PI) staining was used to analysis apoptosis. Immunofluorescence with antibody against cytochrome c (Cyt c) was used to detect Cyt c release from mitochondrion. The results showed U0126 prevented the activation of Erk1/2 maintained by GRP75, but the total Erk1/2 expression was not affected. U0126-treated group showed lower cell viability and higher apoptotic rate compared with control group. Immunofluorescence indicated the delay in release of Cyt c was blocked by U0126. These results suggest U0126 prevents protective effect of GRP75 on PC12 cells by inhibiting Erk1/2 phosphorylation, which certifies that GRP75 can inhibit the mitochondria-dependent apoptotic pathway through Raf/Mek/Erk1/2 signaling cascade.
authors.affiliation: Department of Cellular and Genetic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China.
authors.forename: Hong-yan
authors.initials: HY
authors.lastname: Li
authors.forename: Ling
authors.initials: L
authors.lastname: Yang
authors.forename: Wen
authors.initials: W
authors.lastname: Liu
authors.forename: Ji
authors.initials: J
authors.lastname: Zuo
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002070:Butadienes / Q000494:pharmacology; D002478:Cells, Cultured; D003470:Culture Media; D005947:Glucose / Q000494:pharmacology*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009570:Nitriles / Q000494:pharmacology; D016716:PC12 Cells; D010766:Phosphorylation; D051381:Rats; D048490:raf Kinases / Q000378:metabolism
chemical_list: D002070:Butadienes; D003470:Culture Media; D018840:HSP70 Heat-Shock Proteins; D008565:Membrane Proteins; D009570:Nitriles; C113580:U 0126; C018551:glucose-regulated proteins; D048490:raf Kinases; D048052:Mitogen-Activated Protein Kinase 3; D005947:Glucose