Identification by activity-based probes of a new Plasmodium falciparum E2 ubiquitin conjugating enzyme

ABSTRACT: The ubiquitin-proteasome system (UPS) is essential for Plasmodium falciparum survival and represents a potential target for antimalarial therapies. We utilized a ubiquitin-based activity probe (Ub-Dha) to capture active ubiquitin conjugating machinery during asexual blood-stage development. Several E2 ubiquitin-conjugating enzymes, the E1 activating enzyme, and the HECT E3 ligase PfHEUL were identified and validated through in vitro ubiquitination assays. We also demonstrate selective functional interactions between PfHEUL and a subset of both human and P. falciparum E2s. Additionally, the Ub-Dha probe captured an uncharacterized protein, C0H4U0_PLAF7 with no known homology to ubiquitin-pathway enzymes in other organisms. Through structural and biochemical analysis, we validate it as a novel E2 enzyme, capable of binding ubiquitin in a cysteine-specific manner. These findings contribute to our understanding of the P. falciparum UPS, identifying promising novel drug targets and highlighting the evolutionary uniqueness of the Ub-proteasome system in this parasite.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Plasmodium Falciparum (isolate 3d7)

TISSUE(S): Blood Cell, Blood

DISEASE(S): Malaria

SUBMITTER: Adan Pinto-Fernandez  

LAB HEAD: Adan Pinto-Fernandez

PROVIDER: PXD056473 | Pride | 2025-03-13

REPOSITORIES: Pride