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PTEX helps efficiently traffic haemoglobinases to the food vacuole in Plasmodium falciparum

Thorey K Jonsdottir1,2, Brendan Elsworth1, Simon Cobbold3

  • 1Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia.

Plos Pathogens
|July 31, 2023
PubMed

Insights

The Plasmodium translocon of exported proteins (PTEX) is crucial for parasite survival. This study reveals PTEX also facilitates the trafficking of essential hemoglobin proteases, explaining its vital role in malaria parasite growth within red blood cells.

Area of Science:

  • * Parasitology
  • * Molecular Biology
  • * Biochemistry

Background:

  • * Plasmodium parasites export proteins into host red blood cells (RBCs) for pathogenesis.
  • * The Plasmodium translocon of exported proteins (PTEX) complex mediates protein export across the vacuolar membrane.
  • * PTEX is essential for parasite survival, but only one dependent process (new permeability pathways) was known.

Purpose of the Study:

  • * To identify essential PTEX-dependent proteins and processes beyond the new permeability pathways.
  • * To investigate the function of PTEX150, a core component of the PTEX complex.

Main Methods:

  • * Conditional knockdown of PTEX150 expression in Plasmodium parasites.
  • * Analysis of affected pathways, particularly hemoglobin digestion.
  • * Interaction studies using transgenic parasite lines to examine protease-PTEX relationships.

Main Results:

  • * PTEX150 knockdown significantly impaired hemoglobin digestion, a key parasite process.
  • * Two major hemoglobin proteases, falcipain 2a and plasmepsin II, were found to interact with PTEX components.
  • * Evidence suggests PTEX facilitates the trafficking of these proteases to the cytostome for subsequent food vacuole entry.

Conclusions:

  • * PTEX plays a critical role in the transport of essential hemoglobin proteases.
  • * This protease trafficking is a second essential PTEX-dependent pathway for malaria parasite survival.
  • * The findings provide a new mechanistic understanding of PTEX function in Plasmodium-infected RBCs.

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