Sequence elements within the PEXEL motif and its downstream region modulate PTEX-dependent protein export in Plasmodium falciparum

Gabriela, M; Barnes, CBG; Leong, D; Sleebs, BE; Schneider, MP; Littler, DR; Crabb, BS; de Koning-Ward, TF; Gilson, PR

Author(s): Gabriela, M; Barnes, CBG; Leong, D; Sleebs, BE; Schneider, MP; Littler, DR; Crabb, BS; de Koning-Ward, TF; Gilson, PR;
Details: Publication Year 2023-11-05,Volume 25,Issue #1,Page e12922
Journal Title: Traffic
Abstract: The parasite Plasmodium falciparum causes the most severe form of malaria and to invade and replicate in red blood cells (RBCs), it exports hundreds of proteins across the encasing parasitophorous vacuole membrane (PVM) into this host cell. The exported proteins help modify the RBC to support rapid parasite growth and avoidance of the human immune system. Most exported proteins possess a conserved Plasmodium export element (PEXEL) motif with the consensus RxLxE/D/Q amino acid sequence, which acts as a proteolytic cleavage recognition site within the parasite's endoplasmic reticulum (ER). Cleavage occurs after the P(1) L residue and is thought to help release the protein from the ER so it can be putatively escorted by the HSP101 chaperone to the parasitophorous vacuole space surrounding the intraerythrocytic parasite. HSP101 and its cargo are then thought to assemble with the rest of a Plasmodium translocon for exported proteins (PTEX) complex, that then recognises the xE/D/Q capped N-terminus of the exported protein and translocates it across the vacuole membrane into the RBC compartment. Here, we present evidence that supports a dual role for the PEXEL's conserved P(2) ' position E/Q/D residue, first, for plasmepsin V cleavage in the ER, and second, for efficient PTEX mediated export across the PVM into the RBC. We also present evidence that the downstream 'spacer' region separating the PEXEL motif from the folded functional region of the exported protein controls cargo interaction with PTEX as well. The spacer must be of a sufficient length and permissive amino acid composition to engage the HSP101 unfoldase component of PTEX to be efficiently translocated into the RBC compartment.
Publisher: Wiley
Keywords: Pexel; Ptex; Plasmodium falciparum; chaperone; malaria; protein export; virulence
Research Division(s): Chemical Biology
PubMed ID: 37926971
Publisher's Version: https://doi.org/10.1111/tra.12922
Open Access at Publisher's Site: https://doi.org/10.1111/tra.12922
Terms of Use/Rights Notice: Refer to copyright notice on published article.

Creation Date: 2023-11-20 03:32:51

Last Modified: 2024-03-05 09:29:06