Involvement of protein kinase C pathway in UVC-stimulated phospholipase D2 activity in Vero 76 cells

초록

Phospholipase D (PILD) activity is known to be related to oxidant-induced cellular signaling and membrane disturbance. Previously, an induction of PILD activity in various cell lines by X-ray irradiation was observed. In this study, we examined the effect of UVC radiation on the PILD activity in Vero 76 cells. At a dose of 10 kJ/m(2) Of UVC irradiation, the PLD activity was stimulated approximately 10-fold over the basal activity. This UVC-induced PILD 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. Pre-treatments 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 PILD activity. UVC-stimulated PILD 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 0 forms of PKC by UVC irradiation were observed. These results suggest that the UVC-stimulated PILD activity in Vero 76 cells is mediated through transient phosphorylation of PLD2 by the translocation of PKC to PILD2.

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