Possible involvement of heterotrimeric G proteins in the organization of the Golgi apparatus.

Nordihydroguaiaretic acid (NDGA) caused disassembly of the Golgi apparatus of NRK cells in a dose-, time-, and energy-dependent manner but not in a microtubule-dependent manner. In contrast to brefeldin A, NDGA did not cause release of beta-COP, a component of Golgi-derived vesicles. However, NDGA-induced disassembly was blocked by AlF4-, an activator of the heterotrimeric but not the small GTP-binding proteins. In digitonin-permeabilized cells, guanosine 5'-3-O-(thio)triphosphate (GTPgammaS) as well as AlF4- blocked the NDGA-promoted disassembly of the Golgi apparatus, and Gbetagamma (betagamma subunits of heterotrimeric G proteins) reversed this effect. Our present results suggest the possible involvement of heterotrimeric G proteins in the organization of the Golgi apparatus.