Fig 5. T3SS effector protein secretion is reduced in Shigella strains co-expressing wild-type and inactive Spa47.

A) Representative western blot of the secreted T3SS effector protein IpaC following Congo red activation of Shigella cultures expressing the indicated combinations of Spa47. The cytoplasmic enzyme GAPDH served as a control and was observed in the whole cell extracts (WCE) but not in the supernatant containing the secreted IpaC protein. B) The Western blot intensities were quantified and plotted as the mean ± standard deviation from three blots using independent biological replicates. The quantified protein levels are displayed as a percentage relative to those secreted by the Shigella strain expressing wild-type Spa47. *Indicates a significant difference in IpaC secretion level relative to the wild-type Spa47 complement strain (one-way ANOVA followed by a Dunnett’s post test, p ≤ 0.05)).