Fig. 7. Disruption of the Golgi apparatus by RGSZ1 depends on its G_z binding and GAP function. (A) Lack of the interaction of the mutated RGSZ1 with G_z(QL). The wild-type FLAG-RGSZ1 or E116A/N117A mutant was co-expressed with G_z(QL) in HeLa cells. At 15 hours after transfection, the cells were fixed, and then double-stained with the anti-G_z antibody (a,d) and anti-FLAG antibody (b,e). Merged images are presented on the right (c,f). Bar, 20 µm. (B) HeLa cells transfected with wild-type RGSZ1 (WT; a,b) or mutant RGSZ1 cDNA (E116A/N117A; c,d) were double-stained for FLAG (a,c) and ß-COP (b,d). Arrows indicate RGSZ1-expressing cells. (C) Western blot of extracts of cells expressing the wild-type FLAG-RGSZ1 or E116A/N117A mutant. The cell extracts were subjected to SDS-polyacrylamide gel electrophoresis followed by western blotting using the anti-FLAG antibody. Bands were detected using enhanced chemiluminescence reagents.