title: Toxoplasma DJ-1 Regulates Organelle Secretion by a Direct Interaction with Calcium-Dependent Protein Kinase 1.
abstract: Human DJ-1 is a highly conserved and yet functionally enigmatic protein associated with a heritable form of Parkinson's disease. It has been suggested to be a redox-dependent regulatory scaffold, binding to proteins to modulate their function. Here we present the X-ray crystal structure of theToxoplasmaorthologueToxoplasma gondiiDJ-1 (TgDJ-1) at 2.1-Å resolution and show that it directly associates with calcium-dependent protein kinase 1 (CDPK1). The TgDJ-1 structure identifies an orthologously conserved arginine dyad that acts as a phospho-gatekeeper motif to control complex formation. We determined that the binding of TgDJ-1 to CDPK1 is sensitive to oxidation and calcium, and that this interaction potentiates CDPK1 kinase activity. Finally, we show that genetic deletion of TgDJ-1 results in upregulation of CDPK1 expression and that disruption of the CDPK1/TgDJ-1 complexin vivoprevents normal exocytosis of parasite virulence-associated organelles called micronemes. Overall, our data suggest that TgDJ-1 functions as a noncanonical kinase-regulatory scaffold that integrates multiple intracellular signals to tune microneme exocytosis inT. gondiiIMPORTANCEApicomplexan parasites such asToxoplasmaandPlasmodiumare obligate intracellular parasites that require the protective environment of a host cell in order to replicate and survive within a host organism. These parasites secrete effector proteins from specialized apical organelles to select and invade a chosen host cell. The secretion of these organelles is a tightly regulated process coordinated by endogenous small molecules and calcium-dependent protein kinases. We previously identified theToxoplasmaorthologue of the highly conserved protein DJ-1 as a regulator of microneme secretion, but the molecular basis for this was not known. We have now identified the molecular mechanism for how TgDJ-1 regulates microneme secretion. TgDJ-1 interacts with the kinase responsible for the secretion of these organelles (calcium-dependent kinase 1) and synergizes with calcium to potentiate kinase activity. This interaction is direct, phosphodependent, and necessary for the normal secretion of these important organelles.
authors.affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, California, USA.|Department of Life Sciences, Imperial College London, London, United Kingdom.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Child
authors.affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Megan
authors.initials: M
authors.lastname: Garland
authors.affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Ian
authors.initials: I
authors.lastname: Foe
authors.affiliation: Department of Biochemistry, Redox Biology Center, University of Nebraska, Lincoln, Nebraska, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Madzelan
authors.affiliation: Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA.|Department of Parasitology, National Institute for Medical Research, London, United Kingdom.
authors.forename: Moritz
authors.initials: M
authors.lastname: Treeck
authors.affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Wouter A
authors.initials: WA
authors.lastname: van der Linden
authors.affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Kristina
authors.initials: K
authors.lastname: Oresic Bender
authors.affiliation: Department of Chemistry, Boston College, Chestnut Hill, Massachusetts, USA.
authors.forename: Eranthie
authors.initials: E
authors.lastname: Weerapana
authors.affiliation: Department of Biochemistry, Redox Biology Center, University of Nebraska, Lincoln, Nebraska, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Wilson
authors.affiliation: Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Boothroyd
authors.affiliation: Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA.|Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Reese
authors.affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, California, USA mbogyo@stanford.edu.|Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Bogyo
mesh_terms: D002118:Calcium / Q000378:metabolism; D018360:Crystallography, X-Ray; D005089:Exocytosis; D055354:Exosomes / Q000378:metabolism*; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011485:Protein Binding; D011487:Protein Conformation; D000071617:Protein Deglycase DJ-1 / Q000737:chemistry* / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D014122:Toxoplasma / Q000201:enzymology* / Q000378:metabolism*; D017871:Calcium-Calmodulin-Dependent Protein Kinases
chemical_list: D002118:Calcium; D000071617:Protein Deglycase DJ-1; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases