Proteasome Inhibition Strategies in Malaria Parasites

The proteasome of Plasmodium species represents a validated target for antimalarial intervention, given its central role in regulated protein degradation and cellular homeostasis across all life-cycle stages. Inhibition of parasite proteasomal activity disrupts turnover of damaged or regulatory proteins, leading to accumulation of ubiquitinated substrates, organelle stress and parasite death. Recent efforts have focused on developing inhibitors with high selectivity for the malarial proteasome over its human counterpart, exploiting differences in active-site architecture and subunit composition. Macrocyclic peptides, peptidyl vinyl sulfones and epoxyketones have each emerged as potent chemotypes capable of dual-subunit targeting to limit resistance. Structural studies employing cryo-electron microscopy have elucidated binding modes, resistance-conferring mutations and instances of collateral sensitivity, guiding iterative design to enhance potency and selectivity. Parallel approaches target deubiquitinating enzymes within the ubiquitin–proteasome system, broadening the scope of intervention to upstream regulators of proteostasis. Synergistic combinations of proteasome inhibitors with artemisinins or other partner drugs show promise in restoring efficacy against resistant strains. Collectively, these strategies underscore the global significance of proteasome inhibition as a multifaceted antimalarial paradigm and highlight practical applications in overcoming emerging drug resistance.

Research from Nature Portfolio

High-resolution cryogenic electron microscopy of the Plasmodium falciparum 20S proteasome in complex with a highly selective macrocyclic peptide inhibitor revealed mechanisms underlying species specificity and resistance. Structural comparison between wild-type and mutant proteasomes identified how a single amino-acid substitution reshapes the β6 subunit binding pocket, conferring resistance to one inhibitor while enhancing sensitivity to a tripeptide vinyl sulfone directed at β2 and β5. These insights have informed the design of next-generation compounds capable of engaging multiple catalytic subunits simultaneously, thereby reducing the likelihood of escape mutations and improving in vivo efficacy across both blood and liver stages of infection.

Proteasome Inhibition Strategies in Malaria Parasites publication trend

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

Technical terms

Proteasome: A multimeric protease complex responsible for selective degradation of polyubiquitinated proteins, essential for cellular protein quality control.

Ubiquitin-proteasome system: A cascade in which proteins are tagged with ubiquitin chains and targeted to the proteasome for regulated proteolysis.

Deubiquitinase: An enzyme that removes ubiquitin moieties from substrate proteins, thereby modulating proteasomal targeting and cellular signalling.

Macrocyclic peptide: A peptide whose backbone is cyclised to form a ring, often conferring enhanced binding affinity, specificity and stability.

Covalent inhibitor: A compound designed to form a stable, irreversible bond with a specific amino acid residue in a target enzyme’s active site, prolonging inhibitory effect.

References

1. Structures revealing mechanisms of resistance and collateral sensitivity of Plasmodium falciparum to proteasome inhibitors. Nature Communications (2023).
2. Targeting the Plasmodium falciparum UCHL3 ubiquitin hydrolase using chemically constrained peptides. Proceedings of the National Academy of Sciences of the United States of America (2024).
3. Mitigating the risk of antimalarial resistance via covalent dual-subunit inhibition of the Plasmodium proteasome. Cell Chemical Biology (2023).
4. Covalent Plasmodium falciparum-selective proteasome inhibitors exhibit a low propensity for generating resistance in vitro and synergize with multiple antimalarial agents. PLOS Pathogens (2019).