title: Trafficking of the phosphoprotein PfCRT to the digestive vacuolar membrane in Plasmodium falciparum.
abstract: The digestive vacuole plays an important role in the pathophysiology of the human malaria parasite Plasmodium falciparum. It is a terminal degradation organelle involved in the proteolysis of the host erythrocyte's haemoglobin; it is the site of action of several antimalarial drugs and its membrane harbours transporters implicated in drug resistance. How the digestive vacuole recruits residential proteins is largely unknown. Here, we have investigated the mechanism underpinning trafficking of the chloroquine resistance transporter, PfCRT, to the digestive vacuolar membrane. Nested deletion analysis and site-directed mutagenesis identified threonine 416 as a functional residue for sorting PfCRT to its site of residence. Mass spectroscopy demonstrated that threonine 416 can be phosphorylated. Further phosphorylation was detected at serine 411. Our data establish PfCRT as a phosphoprotein and suggest that phosphorylation of threonine 416 is a possible deciding signal for the sorting of PfCRT to the digestive vacuolar membrane.
authors.affiliation: Hygiene Institut, Abteilung Parasitologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Kuhn
authors.forename: Cecilia P
authors.initials: CP
authors.lastname: Sanchez
authors.forename: Daniel
authors.initials: D
authors.lastname: Ayoub
authors.forename: Theodora
authors.initials: T
authors.lastname: Saridaki
authors.forename: Alain
authors.initials: A
authors.lastname: van Dorsselaer
authors.forename: Michael
authors.initials: M
authors.lastname: Lanzer
mesh_terms: D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D013058:Mass Spectrometry; D026901:Membrane Transport Proteins / Q000378:metabolism*; D008954:Models, Biological; D010766:Phosphorylation; D010963:Plasmodium falciparum; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D015800:Protozoan Proteins / Q000378:metabolism*; D015398:Signal Transduction; D013912:Threonine / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism*
chemical_list: D026901:Membrane Transport Proteins; C416369:PfCRT protein, Plasmodium falciparum; D015800:Protozoan Proteins; D013912:Threonine