Validation of the Protein Kinase PfCLK3 As a Multi-Stage Cross Species Malarial Drug Target

The requirement for next generation anti-malarials to be both curative and transmission blockers necessitate the identification of molecular pathways essential for viability of both asexual and sexual parasite life stages. Here we identify a selective inhibitor to the Plasmodium falciparum protein kinase PfCLK3 which we use in combination with chemogenetics, whole genome sequencing and transcriptomics to validate PfCLK3 as a druggable target acting at multiple parasite life stages. Consistent with the proposed role of PfCLK3 as a regulator of RNA splicing, inhibition results in the down-regulation of >400 genes essential for parasite survival. Through this mechanism, blocking PfCLK3 activity not only results in rapid killing of asexual blood stage parasites but is also effective on sporozoites and gametocytes as well as showing parasiticidal activity in all Plasmodium species tested. Hence, our data establishes PfCLK3 as a target with the potential to deliver both symptomatic treatment and transmission blocking in malaria.