title: Fundamental Roles of the Golgi-Associated Toxoplasma Aspartyl Protease, ASP5, at the Host-Parasite Interface.
abstract: Toxoplasma gondii possesses sets of dense granule proteins (GRAs) that either assemble at, or cross the parasitophorous vacuole membrane (PVM) and exhibit motifs resembling the HT/PEXEL previously identified in a repertoire of exported Plasmodium proteins. Within Plasmodium spp., cleavage of the HT/PEXEL motif by the endoplasmic reticulum-resident protease Plasmepsin V precedes trafficking to and export across the PVM of proteins involved in pathogenicity and host cell remodelling. Here, we have functionally characterized the T. gondii aspartyl protease 5 (ASP5), a Golgi-resident protease that is phylogenetically related to Plasmepsin V. We show that deletion of ASP5 causes a significant loss in parasite fitness in vitro and an altered virulence in vivo. Furthermore, we reveal that ASP5 is necessary for the cleavage of GRA16, GRA19 and GRA20 at the PEXEL-like motif. In the absence of ASP5, the intravacuolar nanotubular network disappears and several GRAs fail to localize to the PVM, while GRA16 and GRA24, both known to be targeted to the host cell nucleus, are retained within the vacuolar space. Additionally, hypermigration of dendritic cells and bradyzoite cyst wall formation are impaired, critically impacting on parasite dissemination and persistence. Overall, the absence of ASP5 dramatically compromises the parasite's ability to modulate host signalling pathways and immune responses.
authors.affiliation: Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland.
authors.forename: Pierre-Mehdi
authors.initials: PM
authors.lastname: Hammoudi
authors.affiliation: Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland.
authors.forename: Damien
authors.initials: D
authors.lastname: Jacot
authors.affiliation: Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland; Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.
authors.forename: Christina
authors.initials: C
authors.lastname: Mueller
authors.affiliation: Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy.
authors.forename: Manlio
authors.initials: M
authors.lastname: Di Cristina
authors.affiliation: Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland.
authors.forename: Sunil Kumar
authors.initials: SK
authors.lastname: Dogga
authors.affiliation: Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Marq
authors.affiliation: Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America.
authors.forename: Julia
authors.initials: J
authors.lastname: Romano
authors.affiliation: Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland.
authors.forename: Nicolò
authors.initials: N
authors.lastname: Tosetti
authors.affiliation: Department of Pathology and Immunology, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland.
authors.forename: Juan
authors.initials: J
authors.lastname: Dubrot
authors.affiliation: Department of Pathology and Immunology, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland.
authors.forename: Yalin
authors.initials: Y
authors.lastname: Emre
authors.affiliation: Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Lunghi
authors.affiliation: Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Coppens
authors.affiliation: Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland; Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, České Budějovice, Czech Republic.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sojka
authors.affiliation: Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland.
authors.forename: Paco
authors.initials: P
authors.lastname: Pino
authors.affiliation: Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland.
authors.forename: Dominique
authors.initials: D
authors.lastname: Soldati-Favre
mesh_terms: D000818:Animals; D057055:Aspartic Acid Proteases / Q000378:metabolism*; D015153:Blotting, Western; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D055786:Gene Knockout Techniques; D006056:Golgi Apparatus / Q000201:enzymology*; D006790:Host-Parasite Interactions / Q000502:physiology*; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D021381:Protein Transport; D060888:Real-Time Polymerase Chain Reaction; D014122:Toxoplasma / Q000201:enzymology / Q000472:pathogenicity*; D014123:Toxoplasmosis / Q000201:enzymology*; D014162:Transfection
chemical_list: D057055:Aspartic Acid Proteases