Figure 9

Capped junctions and invasion failures are significantly reduced for both Toxofilin ⁺and Δ toxofilin tachyzoites when entering in the Δ filamin A (M2) cells. (A, B) Time lapses showing a toxofilin⁺ RON2mC (A) and a Δ toxofilin RON2mC (B) tachyzoite entering in M2 cells; the pink arrowheads define the first and last signs of the junction; DIC and mCherry (green) merged signals (top panels), RON2mC (green) and Myr-Palm-GFP (red) labeled host PM (bottom panels), the trajectories of the parasite apex (blue line), the junction (pink line) and the PM (yellow line) are shown; graphs on the right show the tachyzoite apex (blue), the junction (pink) and the host cell PM (yellow) speeds over time; all scale bars: 5 μm; (C) Histograms comparing the distribution of stable (blue), capped (orange), end-capped (red) junctions and failure (yellow) for toxofilin⁺ and Δ toxofilin tachyzoites when entering in M2 and non-M2 epithelial cells, the absolute numbers are indicated; note the prominence of stable junctions in all cases and the strong reduction in invasion failure, in particular for the mutant parasites; (D) Scatter graphs showing the average speed as a function of time for toxofilin⁺ RON2mC penetrating in M2 (green dots) and non-M2 (blue dots) cells and for Δ toxofilin RON2mC penetrating in M2 (pale green dots) and non-M2 (pale blue dots) cells; note the slightly significantly faster process when the toxofilin⁺ tachyzoites enter M2 cells. DIC, HFF, human foreskin fibroblast; Myr-Palm, myristoylated and palmitoylated; PM, plasma membrane; RON2, RhOptry Neck. (* p< 0.05, ** p< 0.01)