Apicoplast Biology in Malaria Parasites

The apicoplast is a relict, non-photosynthetic plastid found in apicomplexan parasites such as Plasmodium spp. It originated from a secondary eukaryote–eukaryote endosymbiosis and retains four surrounding membranes. This unique organelle orchestrates essential metabolic processes absent from the human host, notably the methylerythritol phosphate (MEP) pathway for isoprenoid-precursor synthesis and a prokaryotic type II fatty acid synthesis pathway active during liver-stage and mosquito-stage development. The apicoplast also hosts iron–sulfur cluster assembly via a dedicated Suf system, redox regulation, haem-related functions and its own genome-encoded gene-expression machinery. Biogenesis and maintenance depend on the coordinated import of nuclear-encoded proteins through transit peptides, the activity of membrane AAA+ proteases for organelle remodelling and precise genome replication. Inhibition of apicoplast functions yields a characteristic delayed death phenotype in blood-stage parasites, a consequence of failed isoprenoid-derived protein prenylation and disrupted intracellular trafficking. Because the apicoplast’s pathways are divergent from those of the host, they present high-value targets for novel antimalarials and potential genetically attenuated vaccines.

Research from Nature Portfolio

Global chemical-proteomic profiling in Plasmodium falciparum has experimentally defined a concise prenylome dominated by Rab GTPases and membrane-associated factors, refining our understanding of apicoplast-derived isoprenoid dependency in post-translational protein modifications. This high-confidence dataset clarifies how limited prenyltransferase substrates underlie essential vesicular trafficking. In a complementary line of enquiry, many clinically used antimalarial compounds have been shown to exhibit potent herbicidal effects against Arabidopsis thaliana, emphasising the shared evolutionary heritage between apicoplast and plant chloroplast pathways. Physicochemical characterisation of these dual-action molecules suggests that plant bioassays can serve as functional surrogates to reveal novel modes of action and inform the design of apicoplast-targeted inhibitors with improved selectivity.

Apicoplast Biology in Malaria Parasites publication trend

The graph below shows the total number of articles in apicoplast biology in malaria parasites across all publications each year (not limited to Nature Index journals).

Technical terms

Apicoplast: A non-photosynthetic plastid in apicomplexan parasites derived from secondary endosymbiosis.

MEP pathway: The methylerythritol phosphate route for synthesising isoprenoid precursors within the apicoplast.

Type II fatty acid synthesis: A prokaryotic-style lipid biosynthesis pathway located in the apicoplast.

Transit peptide: An N-terminal sequence that directs nuclear-encoded proteins to the apicoplast.

Delayed death: A phenotype in which blood-stage parasites arrest growth in the second replication cycle following apicoplast inhibition.

References

1. Malaria parasites require a divergent heme oxygenase for apicoplast gene expression and biogenesis. eLife (2024).
2. The interdependence of isoprenoid synthesis and apicoplast biogenesis in malaria parasites. PLOS Pathogens (2023).
3. Global proteomic analysis of prenylated proteins in Plasmodium falciparum using an alkyne-modified isoprenoid analogue. Scientific Reports (2016).
4. Herbicidal properties of antimalarial drugs. Scientific Reports (2017).
5. The Methylerythritol Phosphate Pathway Is Functionally Active in All Intraerythrocytic Stages of Plasmodium falciparum *. Journal of Biological Chemistry (2004).
6. Type II fatty acid synthesis is essential only for malaria parasite late liver stage development. Cellular Microbiology (2008).
7. The Suf Iron-Sulfur Cluster Synthesis Pathway Is Required for Apicoplast Maintenance in Malaria Parasites. PLOS Pathogens (2013).
8. Compartmentation of Redox Metabolism in Malaria Parasites. PLOS Pathogens (2010).
9. Integrative proteomics and bioinformatic prediction enable a high-confidence apicoplast proteome in malaria parasites. PLOS Biology (2018).
10. Small molecule inhibition of apicomplexan FtsH1 disrupts plastid biogenesis in human pathogens. eLife (2017).
11. Delayed death in the malaria parasite Plasmodium falciparum is caused by disruption of prenylation-dependent intracellular trafficking. PLOS Biology (2019).