The disease that Toxoplasma causes in humans ranges from essentially asymptomatic to debilitating or even fatal. There are likely many reasons for this difference but unambiguous evidence from animal studies and recent data from clinical studies in humans indicate that strain differences in the parasite likely play a major rol. Genetic studies of the parasite have led to the identification of a small number of genes that differ between strains and that interface with the innate immune system in dramatically different ways. The on-going goals of this work are to identify these proteins and determine the molecular basis for their strain-specific effects. In the prior funding period, it was discovered that the recruitment of host mitochondria to the parasitophorous vacuole is a strain-specific phenomenon and the gene responsible for this difference, """"""""mitochondrial-association factor 1"""""""" or MAF1, was identified.
The first aim of the current proposal is to determine how MAF1 recruits mitochondria, the precise nature of the strain-specific differences in its action and the downstream consequences in terms of interactions with the host. Mitochondria are being increasingly recognized as key to innate immune functions and so these differences are likely to play out in important ways in pathogenesis. Macrophages are key players in some of the earliest immune responses and progress in the first funding period revealed a role for several polymorphic Toxoplasma genes in mediating the response of these cells.
The second aim of the current proposal is to identify the genes responsible for two of these strain-specific differences and determine the molecular basis for the downstream effects that are observed.
Both aims will be accomplished through a combination of molecular genetics, imaging and in vivo studies.
The work described here is relevant to the control of important parasitic diseases such as toxoplasmosis and malaria. Specifically, it will increase our understanding of the mechanisms used by these parasites to co-opt the functions of the human cells they infect. Determining how differences between Toxoplasma strains result in different interactions with their human hosts will help optimize treatment for each patient.
|Lorenzi, Hernan; Khan, Asis; Behnke, Michael S et al. (2016) Local admixture of amplified and diversified secreted pathogenesis determinants shapes mosaic Toxoplasma gondii genomes. Nat Commun 7:10147|
|Franco, Magdalena; Panas, Michael W; Marino, Nicole D et al. (2016) A Novel Secreted Protein, MYR1, Is Central to Toxoplasma's Manipulation of Host Cells. MBio 7:e02231-15|
|Coffey, Michael J; Sleebs, Brad E; Uboldi, Alessandro D et al. (2015) An aspartyl protease defines a novel pathway for export of Toxoplasma proteins into the host cell. Elife 4:|
|Pernas, Lena; Adomako-Ankomah, Yaw; Shastri, Anjali J et al. (2014) Toxoplasma effector MAF1 mediates recruitment of host mitochondria and impacts the host response. PLoS Biol 12:e1001845|
|Shastri, Anjali J; Marino, Nicole D; Franco, Magdalena et al. (2014) GRA25 is a novel virulence factor of Toxoplasma gondii and influences the host immune response. Infect Immun 82:2595-605|
|Murphy, James M; Zhang, Qingwei; Young, Samuel N et al. (2014) A robust methodology to subclassify pseudokinases based on their nucleotide-binding properties. Biochem J 457:323-34|
|Reese, Michael L; Shah, Niket; Boothroyd, John C (2014) The Toxoplasma pseudokinase ROP5 is an allosteric inhibitor of the immunity-related GTPases. J Biol Chem 289:27849-58|
|Grover, Harshita Satija; Chu, H Hamlet; Kelly, Felice D et al. (2014) Impact of regulated secretion on antiparasitic CD8 T cell responses. Cell Rep 7:1716-28|
|Ewald, Sarah E; Chavarria-Smith, Joseph; Boothroyd, John C (2014) NLRP1 is an inflammasome sensor for Toxoplasma gondii. Infect Immun 82:460-8|
|Boothroyd, John C (2013) Have it your way: how polymorphic, injected kinases and pseudokinases enable toxoplasma to subvert host defenses. PLoS Pathog 9:e1003296|
Showing the most recent 10 out of 27 publications