DISPERSAL OF GOLGI-APPARATUS IN NOCODAZOLE-TREATED FIBROBLASTS IS A KINESIN-DRIVEN PROCESS

The morphology and location of the Golgi apparatus (GA) has been shown to change upon microtubule (Mt) depolymerization. The GA in different cell types undergoes fragmentation and dispersal throughout the cytop lasm upon treatment with nocodazole. In this study experiments were pe rformed on human skin fibroblasts (HSFs) and rat fibroblasts (REF 52) to determine whether the dispersal of GA in HSFs treated with nocodazo le is dependent on Mts that show the higher resistance to this Mt-depo lymerizing drug. It is shown here that nocodazole at concentrations as low as 100 nM caused the GA to disperse in treated fibroblasts that s till contained a fairly high amount of Mts. Antibody-blocking analysis of Mts after injection of biotin-tubulin into the HSFs was used ts sh ow that nocodazole at low concentrations induced the stabilization of the remaining Mts. The complete disruption of Mts by the incubation of HSFs at 0 degrees C prevented the dispersal of GA from the perinuclea r area when the cells were subsequently warmed to 37 degrees C in the presence of nocodazole. Microinjection of the well-characterized HD an tibody against kinesin but not the preimmune IgG caused inhibition of GA dispersal in HSFs by nocodazole. These data demonstrate that the di spersal of GA in the cytoplasm of nocodazole-treated HSFs is a kinesin -driven process with stable Mts serving as tracks.