mDHFR fusions can clog the PVM translocon and co-block the export of other proteins.

<p>(<b>A-E</b>) Representative images of live <i>P</i>. <i>falciparum</i> parasites grown in the presence (+WR) or absence of WR (control) and expressing the constructs shown schematically above each panel (features as in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005618#ppat.1005618.g001" target="_blank">Fig 1</a>, numbers refer to the length of the amino acids sequence between TM and blocking domain). DIC, differential interference contrast. Arrowheads indicate faint signals at the Maurer’s clefts; arrows show mobile protrusions (note that they do not overlap in the red and the green signal due to movement between capture of the images). Size bars: 5 μm. Schematics to the right show the location of the fusion protein containing the folded WR-bound mDHFR domain (light blue circle with smaller black circle in binding pocket) and the co-expressed REX2 (red line) fused to mCherry (red circle); white box, TM; green circle, GFP; blue line, protease sensitive mutated PH domain. (<b>F</b>) Western analysis of a protease protection assay according to the schematic in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005618#ppat.1005618.g001" target="_blank">Fig 1E</a> with WR treated parasites expressing SBP1-mDHFR-GFP-PH^mut. The construct (detected with α-mDHFR antibodies) is in the PV, as only full length protein or protease resistant cores (after saponin treatment) but no protected fragment indicative of an intact C-terminus is detectable. Calculated molecular weights are, 105 kDa for the full length construct, 48.9 kDa for core I+II and 68.7 kDa for I+II+PH. The asterisk indicates a band likely representing RBC derived hDHFR. Controls are as in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005618#ppat.1005618.g001" target="_blank">Fig 1F</a>. The marker is indicated in kDa.