Unravelling the function of GEXP15, a regulator of Protein Phosphatase type 1, in Plasmodium falciparum

ABSTRACT: The Protein Phosphatase type 1 catalytic subunit (PP1c) works in combination with an array of regulatory proteins to specifically dephosphorylate a diverse range of substrates in the cell. In the human malaria parasite, Plasmodium falciparum, this phosphatase and its regulators are poorly characterized. In this study, we employed a multi-faceted approach to investigate the structural and functional characteristics of a conserved Plasmodium specific regulator known as Gametocyte EXported Protein 15, GEXP15. In-silico study highlights three significant regions of interest, an PP1-interacting RVxF motif located in its N-terminal region, a conserved domain whose function is unknown, and a GYF-like domain that may mediate specific protein-protein interactions. In vitro interaction studies shows that GEXP15 has a direct interaction with PP1 via the RVxF binding motif, enhancing its phosphatase activity. Using transgenic GEXP15-tagged line, confocal microscopy reveals that GEXP15 is highly expressed in late asexual stages and is localized in the parasite nucleus. Immunoprecipitation assays followed by mass spectrometry analyses shows its interaction with ribosomal and RNA binding proteins. Furthermore, pulldown analyses of His-tagged recombinant functional domains of GEXP15 confirm its binding to the ribosomal complex via the GYF domain. Our study provides the first insight into the PfGEXP15-PP1-ribosome interaction, crucial for protein translation, and supports PfGEXP15 as a potential target for malaria drug development.

INSTRUMENT(S): timsTOF Pro

ORGANISM(S): Plasmodium Falciparum (isolate 3d7) Mus Musculus (mouse)

TISSUE(S): Cell Culture

SUBMITTER: Chiara guerrera  

LAB HEAD: Ida Chiara Guerrera

PROVIDER: PXD042114 | Pride | 2023-10-24

REPOSITORIES: Pride