title: Hydrogen peroxide-induced phospholipase D activation and its PKC dependence are modulated by pH changes in PC12 cells.
abstract: Several factors for the hydrogen peroxide (H(2)O(2))-induced PLD stimulation have been proposed, including protein kinase C (PKC), tyrosine kinase, mitogen-activated protein kinase and Ca(2+), but their precise roles remain to be defined. As for involvement of PKC, there has been some discrepancy. Our previous study has demonstrated that phospholipase D (PLD) activity was increased by exposure of PC12 cells to 0.5mM H(2)O(2) in modified Krebs-Ringer buffer (KRB) and suggested that the PLD activation was independent of PKC activity. However, we have shown here that the H(2)O(2)-induced PLD stimulation was much greatly enhanced by incubation in Dulbecco's modified Eagle's medium (DMEM) and further that it was PKC-dependent. These results indicated that the markedly enhanced PLD activation and its PKC dependence were modulated by pH changes during incubation in DMEM. Furthermore, evidence has been presented for possible involvement of alkaline phosphatase in this pH-dependent profile of PLD activation by H(2)O(2).
authors.affiliation: Department of Biochemistry, Gifu University School of Medicine, 500-8705, Gifu, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Banno
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Nozawa
mesh_terms: D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects; D006706:Homeostasis / Q000502:physiology; D006861:Hydrogen Peroxide / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D009097:Multienzyme Complexes; D016716:PC12 Cells; D010739:Phospholipase D / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism*; D011493:Protein Kinase C / Q000737:chemistry* / Q000378:metabolism*; D051381:Rats
chemical_list: D009097:Multienzyme Complexes; D006861:Hydrogen Peroxide; D011493:Protein Kinase C; D010739:Phospholipase D