RhoBTB3 depletion leads to Golgi fragmentation and increased cell size. (A) Confocal microscopy of HeLa cells transfected for 72 h with control siRNA or two RhoBTB3 siRNAs as indicated and stained for GCC185. Red staining at right is TRITC-siRNA. Yellow asterisks indicate nondepleted cells. Bar, 20 µm. (B and C), High magnification of Golgi with control (B) or RhoBTB3-siRNA (C); anti-GCC185 is shown in green; anti-GM130 is shown in red. Merged images are presented in the far-left column. Bar, 8 µm. (D) Immunoblot detection of RhoBTB3 depletion in HeLa cells; molecular mass marker mobility is shown at the left in kilodaltons. (E) quantification of Golgi fragmentation in siRNA-treated cells. t test; *, P < 0.05; error bars represent SEM; n = 3. (F) flow cytometry analysis of cell size with the indicated siRNAs. A representative example from one of three independent experiments is shown.