Certain non-canonical PEXEL/HT variants are functional in a REX3 reporter. A. Fluorescence microscopy. The structure of full-length REX3 is indicated at the top; the schematic structure of the reporter proteins is depicted on the left of representative images of iRBCs. The ER-signal is shaded blue, the (non-)canonical PEXEL/HT is shaded black and GFP is shaded green. Putative cleavage sites are indicated by an arrow (blue: SP cleavage site; black: Plasmepsin V cleavage site). efficient export of REX3-RQLSE-GFP (63% export, indicating some reduction due to GFP-tagging) and REX3-RQISE-GFP, whereas REX3-KQLSE-GFP and REX3-HQLSE-GFP showed a reduced level of export . By contrast, REX3-KQISE-GFP, REX3-HQISE-GFP and the control reporter (REX3-AQLSE-GFP) were not exported. Schulze J, Kwiatkowski M, Borner J, Schlüter H, Bruchhaus I, Burmester T, Spielmann T, Pick C. The Plasmodium falciparum exportome contains non-canonical PEXEL/HT proteins. Mol Microbiol. 2015 Apr 8. [Epub ahead of print]

The hyp11 protein encoded by PFA0610c is an exported protein with a non-canonical PEXEL/HT. A. Fluorescence microscopy. The schematic structure of the GFP-tagged proteins is depicted on the left of representative images of iRBCs.The ER-signal is shaded blue, the (non-) canonical PEXEL/HT is shaded black and GFP is shaded green. Putative cleavage sites are indicated by an arrow (blue: SP cleavage site; black: Plasmepsin V cleavage site. B. Immunofluorescence analyses. Antibodies against GFP and the Maurer’s clefts protein were used. Membranes were stained with Bodipy-TR-C5ceramide. The fluorescence of GFP-tagged PFA0610c (01128-RIIAE-GFP), a protein with a R.I.E variant, appeared to be located close to the RBC membrane (A). 01128-RIIAE-GFP did not colocalize with REX2 (B).This indicates that PFA0610cis associated with the RBC membrane. Schulze J, Kwiatkowski M, Borner J, Schlüter H, Bruchhaus I, Burmester T, Spielmann T, Pick C. The Plasmodium falciparum exportome contains non-canonical PEXEL/HT proteins. Mol Microbiol. 2015 Apr 8. [Epub ahead of print]