Loss of Serine/Threonine Protein Phosphatase 6 Severely Impairs Sexual Stage Development in Malaria Parasite Plasmodium berghei

ABSTRACT: Protein phosphorylation plays a critical role during the development of malaria parasites. Here, we performed a functional analysis of the Plasmodium berghei Ser/Thr protein phosphatase 6 (PbPP6), which was associated with the plasma membrane of macrogametes and ookinetes. Compared to wild-type P. berghei, genetic disruption/deletion of the pbpp6 gene (∆pbpp6) reduced the asexual growth of the parasites and prolonged the survival of ∆pbpp6-infected mice. The ∆pbpp6 parasites showed impaired gametogenesis, particularly affecting male gametogenesis, which substantially decreased ookinete formation and transmission to mosquitoes. RNA-seq assays revealed that pbpp6 disruption led to over 11-fold down-regulation of the nek3 gene, a regulator of MAPK2 in the PKG-Ca2+ signaling cascade during male gametogenesis. Several PDEs (α, γ, δ) were also affected, indicating that PbPP6 plays a role in the cGMP-PKG-Ca2+ signaling pathway. Additionally, we observed altered expression of messenger ribonucleoproteins in the Δpbpp6 parasites, which may affect translational repression of stored mRNAs in female gametocytes and post-fertilization development in mosquitoes. Consistent with the dysregulated GO terms related to the cGMP-PKG-Ca2+ signaling cascade observed in RNA-seq analysis, the activated gametocytes of ∆pbpp6 exhibited significantly reduced levels of intracellular cGMP, cytosolic Ca2+ mobilization, and DNA replication. Phosphoproteomic analysis detected increased phosphorylation at the Ser508 site of guanylyl cyclase alpha (GCα), suggesting that PbPP6 regulates cGMP-PKG-Ca2+ signaling cascades by modulating the activity of GCα during gametogenesis. This study highlights the potential of targeting PP6 to disrupt malaria transmission.

INSTRUMENT(S): timsTOF Pro

ORGANISM(S): Plasmodium Berghei

TISSUE(S): Gametocyte

SUBMITTER: Xiaotong Zhu  

LAB HEAD: Xiaotong Zhu

PROVIDER: PXD063225 | Pride | 2025-06-03

REPOSITORIES: Pride