FIG. 3.

Interaction of SseF and SseG. (A) Competitive index analysis of Salmonella mutant strains. The competitive indices of wild type (wt) versus sseG (n = 3) and of wt versus sseF (n = 6) are not significantly different (P = 0.71) but are significantly (P = 0.0012) or very significantly (P = 0.0006) lower than 1, respectively. The competitive indices of sseG versus sseF sseG (n = 3; P = 0.30) and sseF versus sseF sseG (n = 4; P = 0.12) are not significantly different from 1. These data indicate that the two genes are functionally linked. (B) GST-SseF bound to beads was incubated with extracts of HeLa cells expressing myc-tagged Salmonella effectors. Total lysates and proteins bound to washed beads were analyzed by Western blotting using an anti-myc antibody. (C) HeLa cells were cotransfected with plasmids coding for myc- and HA-tagged effector proteins as indicated, lysed, and immunoprecipitated (IP) using an anti-myc antibody coupled to Sepharose beads. HA-tagged proteins present in lysates (upper panels) and coimmunoprecipitated with myc-tagged effectors (lower panel) were analyzed by Western blotting (WB). The lysate membrane was reanalyzed for myc-tagged proteins (encircled bands, middle panel). Controls indicated the effective binding of myc-tagged proteins to the beads (data not shown). The top and bottom bands seen after anti-myc immunoprecipitation (lower panel) correspond to mouse IgG heavy and light chains.