Involvement of protein kinase C pathway in UVC-stimulated phospholipase D2 activity in Vero 76 cells.
Phospholipase D (PLD) activity is known to be related to oxidant-induced cellular signaling and membrane disturbance. Previously, an induction of PLD activity in various cell lines by X-ray irradiation was observed. In this study, we examined the effect of UVC radiation on the PLD activity in Vero 76 cells. At a dose of 10 kJ/m2 of UVC irradiation, the PLD activity was stimulated approximately 10-fold over the basal activity. This UVC-induced PLD activity was found to be dependent on the presence of extracellular calcium and was inhibited by catalase as well as amifostine-an intracellular thiol antioxidant. Pretreatments with Ro32-0432-a selective inhibitor of protein kinase C (PKC)-and downregulation of PKC by preincubation of phorbol 12-myristate 13-acetate significantly inhibited the UVC-induced PLD activity. UVC-stimulated PLD activity was observed only in murine PLD2 (mPLD2)-transfected Vero 76 cells and not in human PLD1 (hPLD1)-transfected cells. Transient incorporation of PKC with mPLD2 and the phosphorylation of mPLD2 by a and b forms of PKC by UVC irradiation were observed. These results suggest that the UVC-stimulated PLD activity in Vero 76 cells is mediated through transient phosphorylation of PLD2 by the translocation of PKC to PLD2.
Kim
Sungyeul
S
School of Chemistry, Seoul National University, Seoul 151-747, Korea.
Choi
Myung Sun
MS
Choi
Myung Un
MU
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002614:Chelating Agents / Q000494:pharmacology; D002522:Chlorocebus aethiops; D004789:Enzyme Activation / Q000528:radiation effects; D051379:Mice; D010739:Phospholipase D / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017382:Reactive Oxygen Species; D015398:Signal Transduction / Q000528:radiation effects*; D014466:Ultraviolet Rays; D014709:Vero Cells
D000975:Antioxidants; D002614:Chelating Agents; D020033:Protein Isoforms; D047428:Protein Kinase Inhibitors; D017382:Reactive Oxygen Species; D011493:Protein Kinase C; C105606:phospholipase D2; D010739:Phospholipase D; D002118:Calcium