title: Analysis of the interactome of the Ser/Thr Protein Phosphatase type 1 in Plasmodium falciparum.
abstract: BACKGROUND
  Protein Phosphatase 1 (PP1) is an enzyme essential to cell viability in the malaria parasite Plasmodium falciparum (Pf). The activity of PP1 is regulated by the binding of regulatory subunits, of which there are up to 200 in humans, but only 3 have been so far reported for the parasite. To better understand the P. falciparum PP1 (PfPP1) regulatory network, we here report the use of three strategies to characterize the PfPP1 interactome: co-affinity purified proteins identified by mass spectrometry, yeast two-hybrid (Y2H) screening and in silico analysis of the P. falciparum predicted proteome.
  
  
  RESULTS
  Co-affinity purification followed by MS analysis identified 6 PfPP1 interacting proteins (Pips) of which 3 contained the RVxF consensus binding, 2 with a Fxx[RK]x[RK] motif, also shown to be a PP1 binding motif and one with both binding motifs. The Y2H screens identified 134 proteins of which 30 present the RVxF binding motif and 20 have the Fxx[RK]x[RK] binding motif. The in silico screen of the Pf predicted proteome using a consensus RVxF motif as template revealed the presence of 55 potential Pips. As further demonstration, 35 candidate proteins were validated as PfPP1 interacting proteins in an ELISA-based assay.
  
  
  CONCLUSIONS
  To the best of our knowledge, this is the first study on PfPP1 interactome. The data reports several conserved PP1 interacting proteins as well as a high number of specific interactors to PfPP1. Their analysis indicates a high diversity of biological functions for PP1 in Plasmodium. Based on the present data and on an earlier study of the Pf interactome, a potential implication of Pips in protein folding/proteolysis, transcription and pathogenicity networks is proposed. The present work provides a starting point for further studies on the structural basis of these interactions and their functions in P. falciparum.
authors.affiliation: Center for Infection and Immunity of Lille, Inserm U1019-CNRS UMR 8204, University of Lille Nord de France, Institut Pasteur de Lille, 1 Rue du Professeur Calmette, Lille, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hollin
authors.affiliation: Center for Infection and Immunity of Lille, Inserm U1019-CNRS UMR 8204, University of Lille Nord de France, Institut Pasteur de Lille, 1 Rue du Professeur Calmette, Lille, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: De Witte
authors.affiliation: Center for Infection and Immunity of Lille, Inserm U1019-CNRS UMR 8204, University of Lille Nord de France, Institut Pasteur de Lille, 1 Rue du Professeur Calmette, Lille, France.
authors.forename: Astrid
authors.initials: A
authors.lastname: Lenne
authors.affiliation: Center for Infection and Immunity of Lille, Inserm U1019-CNRS UMR 8204, University of Lille Nord de France, Institut Pasteur de Lille, 1 Rue du Professeur Calmette, Lille, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Pierrot
authors.affiliation: Center for Infection and Immunity of Lille, Inserm U1019-CNRS UMR 8204, University of Lille Nord de France, Institut Pasteur de Lille, 1 Rue du Professeur Calmette, Lille, France. jamal.khalife@pasteur-lille.fr.
authors.forename: Jamal
authors.initials: J
authors.lastname: Khalife
mesh_terms: D020816:Amino Acid Motifs; D010963:Plasmodium falciparum / Q000201:enzymology*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D054645:Protein Phosphatase 1 / Q000378:metabolism*; D020543:Proteome; D015800:Protozoan Proteins / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D020543:Proteome; D015800:Protozoan Proteins; D054645:Protein Phosphatase 1
keywords: Interactome; PP1; Plasmodium; RVxF motif