Salmonella Typhimurium effector SseI inhibits chemotaxis and increases host cell survival by deamidation of heterotrimeric Gi proteins
Fig 5
Influence of SseI on directed migration of dendritic cells.
(A-C) DCs were infected with GFP-expressing wild type (wt)- or ΔsseI-Salmonella (MOI = 30; 30 min). Then, cells were transferred into a collagen matrix. (A) A CCL19 gradient was applied and directed migration for 4 h was determined via time-lapse microscopy. Red dots mark the end of the migration tracks. Every track starts at x = 0 / y = 0. (B) Tracks of n = 30 randomly selected DCs for each condition from 3 independent experiments were quantified and the chemotactic index was determined with Chemotaxis and Migration tool V2.0 (Ibidi). (C) Similarly, the speed of migration was quantified. Statistical significance was assessed using ANOVA with Bonferroni post-test. (D) DCs infected with wt- or ΔsseI-Salmonella (MOI = 30; 30 min) were lysed at the indicated times and immunoblot analysis was performed with indicated antibodies (GαQE, p-Akt, Akt and actin). (E-G) Migration of DCs after ectopical expression of wild type (wt) SseI or SseI-C178A (C178A). Cells were transferred into a collagen matrix, a CCL19 gradient was applied, and directed migration (E) was determined by time-lapse microscopy (wt SseI, n = 43; SseI-C178A, n = 49). Cells were randomly selected from 3 independent experiments. (F, G) Quantification of the chemotactic index (F) and speed (G) of DCs. Statistical significance was assessed using unpaired, two-tailed Students t-test.