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]