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. 2019 Nov 14;15(11):e1007928. doi: 10.1371/journal.ppat.1007928

Fig 4. A docking-competent conformation is established within 10 minutes of initial contact of S. flexneri with cells.

Fig 4

Induction of disulfide crosslinking of IpaC cysteine substitution derivatives by addition of the oxidant copper 10 minutes after initial bacterial contact with cells. (a) Representative micrographs of S. flexneri-infected cells, imaged at 50 minutes of infection, so as to allow production of GFP from TSAR. Blue, DNA; red, mCherry (bacteria). Scale bar, 50 μM. (b) Quantification of docked bacteria per cell, in experiments represented in panel a. (c) Percent of docked bacteria that activated secretion, as measured by the TSAR reporter. (d) Representative non-reducing western blot of IpaC in plasma membrane-enriched fractions, showing dimer formation by IpaC A38C in the presence of copper. (e) Densitometry analysis of bands corresponding to the IpaC dimer in experiments represented in panel d. Graphed data are presented as mean ± SEM of three or more independent experiments. N.S., not significant; **, P<0.01. Two-way ANOVA with Sidak post hoc test.