POSSIBLE INVOLVEMENT OF HETEROTRIMERIC G-PROTEINS IN THE ORGANIZATIONOF THE GOLGI-APPARATUS

Nordihydroguaiaretic acid (NDGA) caused disassembly of the Golgi appar atus of NRK cells in a dose-, time-, and energy-dependent manner but n ot in a microtubule-dependent manner, In contrast to brefeldin A, NDGA did not cause release of beta-COP, a component of Golgi-derived vesic les, However, NDGA-induced disassembly was blocked by AlF4-, an activa tor of the heterotrimeric but not the small GTP-binding proteins. In d igitonin-permeabilized cells, guanosine 5'-3-O-(thio)triphosphate (GTP gamma S) as well as AlF4- blocked the NDGA-promoted disassembly of th e Golgi apparatus, and G beta gamma (beta gamma subunits of heterotrim eric G proteins) reversed this effect, Our present results suggest the possible involvement of heterotrimeric G proteins in the organization of the Gels apparatus.