Fig. 6: SopB recruits EXOC2 and EXOC3 to STm invasion sites via independent pathways.

a Protein map of SopB depicting the mutation sites introduced in this study: L76P and L84P were mutated to interrupt SopB’s direct binding with CDC42 while C460S was mutated to disrupt SopB’s PI phosphatase activity. b, c Representative images (b) and quantifications (c) of EXOC2 recruitment to STm invasion sites. WT Henle 407 cells were transfected with GFP-EXOC2 and then infected with indicated STm strains. Cells were fixed and imaged at 10 min post-infection. n = 3 Independent experiments with 100 invasion sites examined in each experiment. d Quantifications of EXOC3 recruitment to STm invasion sites. WT Henle 407 cells were transfected with GFP-EXOC3 and then infected with indicated STm strains. Cells were fixed and imaged at 10 min post-infection. n = 3 Independent experiments with 100 invasion sites examined in each experiment. e Representative images and line plot profiles (white arrows in insets in upper panel) depicting EXOC3 and CDC42’s colocalization on Golgi membrane (GM130⁺) prior to STm infection and recruited to invasion site with STm infection. WT Henle were transfected with GFP-EXOC3 and myc-CDC42 and stained for GM130 and myc-CDC42 (upper panel), or were infected with WT STm and fixed and imaged at 10 min post-infection, actin and STm staining were used to identify invasion sites (lower panel). MCC values for GFP-EXOC3 and myc-CDC42 are M1 = 0.55 ± 0.02 and M2 = 0.42 ± 0.08. Data are representative of three independent experiments. f, g Representative images (f) and quantifications (g) of EXOC3 recruitment to STm invasion sites. WT or CDC42 KO Henle 407 cells were transfected with GFP-EXOC3 and then infected with WT STm. Cells were fixed and imaged at 10 min post-infection. n = 3 Independent experiments with 100 invasion sites examined in each experiment. h Quantifications of EXOC2 recruitment to STm invasion sites. WT or CDC42 KO Henle 407 cells were transfected with GFP-EXOC2 and then infected with WT STm. Cells were fixed and imaged at 10 min post-infection. n = 3 Independent experiments with 100 invasion sites examined in each experiment. Data shown are means ± SD. P value was calculated using c, d one-way ANOVA and g, h two-tailed unpaired t test. Scale bars, 10 μm. Source data are provided as a Source Data file.