Possible Involvement of Heterotrimeric G Proteins in the Organization of the Golgi Apparatus

Abstract 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 β-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 (GTPγS) as well as AlF4 − blocked the NDGA-promoted disassembly of the Golgi apparatus, and Gβγ (βγ 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.