RicA inhibits host secretion and causes fragmentation of the Golgi apparatus. (A) Representative Western blotting of levels of expression of HA-BspB and myc-RicA (individually or in combination) in HeLa cells (left) and analysis of SEAP secretion by HeLa cells expressing HA-BspB and myc-RicA (individually or in combination) (right). Values are means ± SD of results from 3 independent experiments. Asterisks indicate a statistically significant difference compared to control cells, assessed using one-way analysis of variance (ANOVA) followed by a Dunnett’s multicomparison test. (B) Quantification of Golgi fragmentation in BMMs transduced to express GFP (control), GFP-Rab2aS20N, HA-BspB, GFP-RicA, or both HA-BspB and GFP-RicA. Fragmentation was scored as presenting at least 4 disconnected GM130-positive structures (30). Values are means ± SD of results from at least 3 independent experiments. Asterisks indicate a statistically significant difference compared to control cells, assessed using one-way analysis of variance (ANOVA) followed by a Dunnett’s multicomparison test; ns, not significant. (C) Representative confocal micrographs of BMMs expressing GFP, GFP-Rab2aS20N, HA-BspB, GFP-RicA, or both HA-BspB and GFP-RicA and stained for Golgi apparatus detection using an anti-GM130 antibody. Arrows indicate Golgi fragments. Scale bar, 10 μm.