title: Roles of tyrosine phosphorylation and cleavage of protein kinase Cdelta in its protective effect against tumor necrosis factor-related apoptosis inducing ligand-induced apoptosis.
abstract: Protein kinase Cdelta (PKCdelta) regulates cell apoptosis in a cell- and stimulus-specific manner. Here, we studied the role of PKCdelta in the apoptotic effect of TRAIL in glioma cells. We found that transfection of the cells with a PKCdelta kinase-dead mutant (K376R) or with a small interfering RNA targeting the PKCdelta mRNA increased the apoptotic effect of tumor necrosis factor-related apoptosis inducing ligand (TRAIL), whereas overexpression of PKCdelta decreased it. PKCdelta acted downstream of caspase 8 and upstream of cytochrome c release from the mitochondria. TRAIL induced cleavage of PKCdelta within 2-3 h of treatment, which was abolished by caspase 3, 8, and 9 inhibitors. The cleavage of PKCdelta was essential for its protective effect because overexpression of a caspase-resistant mutant (PKCdeltaD327A) did not protect glioma cells from TRAIL-induced apoptosis but rather increased it. TRAIL induced translocation of PKCdelta to the perinuclear region and the endoplasmic reticulum and phosphorylation of PKCdelta on tyrosine 155. Using a PKCdeltaY155F mutant, we found that the phosphorylation of PKCdelta on tyrosine 155 was essential for the cleavage of PKCdelta in response to TRAIL and for its translocation to the endoplasmic reticulum. In addition, phosphorylation of PKCdelta on tyrosine 155 was necessary for the activation of AKT in response to TRAIL. Our results indicate that PKCdelta protects glioma cells from the apoptosis induced by TRAIL and implicate the phosphorylation of PKCdelta on tyrosine 155 and its cleavage as essential factors in the anti-apoptotic effect of PKCdelta.
authors.affiliation: Gonda (Goldschmied) Medical Diagnosis Research Center, Faculty of Life-Sciences, Bar-Ilan University, Ramat-Gan, Israel 52900.
authors.forename: Hana
authors.initials: H
authors.lastname: Okhrimenko
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.forename: Cunli
authors.initials: C
authors.lastname: Xiang
authors.forename: Donghong
authors.initials: D
authors.lastname: Ju
authors.forename: Peter M
authors.initials: PM
authors.lastname: Blumberg
authors.forename: Ruth
authors.initials: R
authors.lastname: Gomel
authors.forename: Gila
authors.initials: G
authors.lastname: Kazimirsky
authors.forename: Chaya
authors.initials: C
authors.lastname: Brodie
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins; D045744:Cell Line, Tumor; D005455:Fluorescent Antibody Technique; D005910:Glioma / Q000473:pathology; D006801:Humans; D006868:Hydrolysis; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism*; D051745:Protein Kinase C-delta; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D051017:Apoptosis Regulatory Proteins; D008562:Membrane Glycoproteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; C505654:Tnfsf10 protein, mouse; D014409:Tumor Necrosis Factor-alpha; D014443:Tyrosine; C497259:Prkcd protein, mouse; C497258:PRKCD protein, human; D011493:Protein Kinase C; D051745:Protein Kinase C-delta