title: The chaperonin TRiC forms an oligomeric complex in the malaria parasite cytosol.
abstract: The malaria parasite exports numerous proteins into its host red blood cell (RBC). The trafficking of these exported effectors is complex. Proteins are first routed through the secretory system, into the parasitophorous vacuole (PV), a membranous compartment enclosing the parasite. Proteins are then translocated across the PV membrane in a process requiring ATP and unfolding. Once in the RBC compartment the exported proteins are then refolded and further trafficked to their final localizations. Chaperones are important in the unfolding and refolding processes. Recently, it was suggested that the parasite TRiC chaperonin complex is exported, and that it is involved in trafficking of exported effectors. Using a parasite-specific antibody and epitope-tagged transgenic parasites we could observe no export of Plasmodium TRiC into the RBC. We tested the importance of the parasite TRiC by creating a regulatable knockdown line of the TRiC-θ subunit. Loss of the parasite TRiC-θ led to a severe growth defect in asexual development, but did not alter protein export into the RBC. These observations indicate that the TRiC proteins play a critical role in parasite biology, though their function, within the parasite, appears unrelated to protein trafficking in the RBC compartment.
authors.affiliation: Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, 63110, USA.
authors.forename: Natalie J
authors.identifier: 0000-0002-3454-1636
authors.initials: NJ
authors.lastname: Spillman
authors.affiliation: Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, 63110, USA.
authors.forename: Josh R
authors.initials: JR
authors.lastname: Beck
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.
authors.forename: Suresh M
authors.initials: SM
authors.lastname: Ganesan
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.
authors.forename: Jacquin C
authors.initials: JC
authors.lastname: Niles
authors.affiliation: Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, 63110, USA.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Goldberg
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D018833:Chaperonins / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism*; D004912:Erythrocytes / Q000469:parasitology; D005786:Gene Expression Regulation / Q000235:genetics; D006801:Humans; D016778:Malaria, Falciparum / Q000469:parasitology / Q000473:pathology*; D046912:Multiprotein Complexes / Q000378:metabolism*; D010963:Plasmodium falciparum / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D058849:Protein Refolding; D021381:Protein Transport / Q000502:physiology; D014617:Vacuoles / Q000469:parasitology
chemical_list: D046912:Multiprotein Complexes; D018833:Chaperonins
keywords: T-complex protein; TRiC; chaperonin; malaria; protein export; regulatable expression