Cellular stress and phospholipase d activity: Effect of γ-radiation on animal cells

Phospholipase D (PLD) activity has been implicated in many cellular signaling events. Here we are presenting an experimental fact of alteration of PLD activity by radiation stress. VERO 76, L 1210 and P 388 cells were irradiated with γ-ray and PLD products, [¹⁴C]phosphatate and [¹⁴C]phosphatidyl ethanol were quantitated. The time dependence and dose dependence of PLD activity on irradiation were studied. In VERO 76 and L 1210 cells, the PLD activities were stimulated in response of Y -radiation and were maxima at 20 Gy dose. Whereas P 388 and SNU 16 cells showed no PLD activation effect of γ-ray at 20 Gy dose. However the PLD activity in these cell lines was promoted at higher dose (90 Gy), especially for the P 388 cell. When the dependence of time was investigated at 20 Gy irradiated cells, phosphatate and phosphatidyl ethanol levels increased immediately (0 hr) after irradiation and reached to above 150-200 % of the control levels of VERO 76 and L 1210. The PLD activity was diminished during 1 hr incubation after irradiation and disappeared at 3 hr postirradiation. [Supported by Center for Molecular Catalysis, Korea Science and Engineering Foundation).