Arachidonyltrifluoromethy ketone, a phospholipase A(2) antagonist, inducesdispersal of both Golgi stack- and trans Golgi network-resident proteins throughout the cytoplasm

Arachidonyltrifluoromethy ketone (AACOCF(3)), a phospholipase A(2) antagoni st, reversibly induced dispersal of Golgi stack- and trans Gels network (TG N)-resident proteins throughout the cytoplasm in NRK cells as followed by i mmunocytochemical staining of ManII and TGN38, respectively. The action of AACOCF(3) was partly blocked by other PLA(2) antagonists, suggesting it be not caused by a general inhibition of phospholipase A(2). AACOCF(3) neither dissociated beta -COP from membranes nor prevented brefeldin A-induced bet a -COP release. Action of AACOCF(3) on the Golgi stack and TGN is different from that of brefeldin A and nordihydroguaiaretic acid. The most prominent difference is that the Golgi stack and TGN showed a similar sensitivity to AACOCF(3), while the TGN was dispersed more slowly than the Golgi stack in brefeldin A- or nordihydroguaiaretic acid-treated NRK cells. This novel ac tion of AACOCF(3) may be used as pharmacological tool and give new insights into vesicle-mediated traffic and Golgi membrane dynamics. (C) 2001 Academ ic Press.