title: Diacylglycerol kinase regulation of protein kinase D during oxidative stress-induced intestinal cell injury.
abstract: We recently demonstrated that protein kinase D (PKD) exerts a protective function during oxidative stress-induced intestinal epithelial cell injury; however, the exact role of DAG kinase (DGK)zeta, an isoform expressed in intestine, during this process is unknown. We sought to determine the role of DGK during oxidative stress-induced intestinal cell injury and whether DGK acts as an upstream regulator of PKD. Inhibition of DGK with R59022 compound or DGKzeta siRNA transfection decreased H2O2-induced RIE-1 cell apoptosis as measured by DNA fragmentation and increased PKD phosphorylation. Overexpression of kinase-dead DGKzeta also significantly increased PKD phosphorylation. Additionally, endogenous nuclear DGKzeta rapidly translocated to the cytoplasm following H2O2 treatment. Our findings demonstrate that DGK is involved in the regulation of oxidative stress-induced intestinal cell injury. PKD activation is induced by DGKzeta, suggesting DGK is an upstream regulator of oxidative stress-induced activation of the PKD signaling pathway in intestinal epithelial cells.
authors.affiliation: Department of Surgery, The University of Texas Medical Branch, 301 University Blvd., Children's Hospital Room 3.200-E, Galveston, TX 77555-0353, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Song
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Mourot
authors.forename: B Mark
authors.initials: BM
authors.lastname: Evers
authors.forename: Dai H
authors.initials: DH
authors.lastname: Chung
mesh_terms: D000818:Animals; D017209:Apoptosis; D002467:Cell Nucleus / Q000201:enzymology; D002478:Cells, Cultured; D003593:Cytoplasm / Q000201:enzymology; D019852:Diacylglycerol Kinase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000201:enzymology*; D018384:Oxidative Stress; D011493:Protein Kinase C / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D051381:Rats
chemical_list: D006861:Hydrogen Peroxide; C526463:DGKZ protein, human; D019852:Diacylglycerol Kinase; C089212:protein kinase D; D011493:Protein Kinase C