Publications & Reports

Functional inactivation of Plasmodium falciparum glycogen synthase kinase GSK3 modulates erythrocyte invasion and blocks gametocyte maturation.

Alder A, Wilcke L, Pietsch E, von Thien H, Pazicky S, Löw C, Mesen-Ramirez P, Bachmann A, Burda PC, Kunick C, Sondermann H, Wilson D, Gilberger TW
CSSB Centre for Structural Systems Biology, 22607 Hamburg, Germany; Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; University of Hamburg, 20146 Hamburg, Germany.

Abstract

Malaria is responsible for hundreds of thousands of deaths every year. The lack of an effective vaccine and the global spread of multi-drug resistant parasites hampers the fight against the disease and underlines the need for new antimalarial drugs. Central to the pathogenesis of malaria is the proliferation of Plasmodium parasites within human erythrocytes. Parasites invade erythrocytes via a coordinated sequence of receptor-ligand interactions between the parasite and the host cell. Post-translational modifications such as protein phosphorylation are known to be key regulators in this process and are mediated by protein kinases. For several parasite kinases, including the Plasmodium falciparum Glycogen Synthase Kinase 3 (PfGSK3), inhibitors have been shown to block erythrocyte invasion. Here, we provide an assessment of PfGSK3 function by reverse genetics. Using targeted gene disruption, we show the active gene copy, PfGSK3beta, is not essential for asexual blood stage proliferation, although it modulates efficient erythrocyte invasion. We found functional inactivation leads to a 69% decreased growth rate and confirmed this growth defect by rescue experiments with wild-type and catalytically inactive mutants. Functional knock-out of PfGSK3beta does not lead to transcriptional up-regulation of the second copy of PfGSK3. We further analyze expression, localization, and function of PfGSK3beta during gametocytogenesis using a parasite line allowing conditional induction of sexual commitment. We demonstrate PfGSK3beta-deficient gametocytes show a strikingly malformed morphology leading to the death of parasites in later stages of gametocyte development. Taken together, these findings are important for our understanding and the development of PfGSK3 as an anti-malarial target.

Link to publisher’s web site

Publication

  • Journal: The Journal of Biological Chemistry
  • Published: 09/08/2022
  • Volume: 298
  • Issue: 9
  • Pagination: 102360

Download