Strain-specific activation of the NF-kappa B pathway by GRA15, a novel Toxoplasma gondii dense granule protein
Name
Rosowski-2011-Strain-specific activation of the NF-kappa B pathway by GRA15, a novel Toxoplasma gondii dense granule protein.pdf
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2.67 MB
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Author(s)
Rosowski, Emily Elizabeth
Lu, Diana
Julien, Lindsay
Rodda, Lauren B.
Gaiser, Rogier A.
Saeij, Jeroen
Jensen, Kirk D.
Date Issued
January 2011
Journal
Journal of Experimental Medicine
Publisher
Rockefeller University Press
Citation
Rosowski, E. E. et al. “Strain-specific Activation of the NF- B Pathway by GRA15, a Novel Toxoplasma Gondii Dense Granule Protein.” Journal of Experimental Medicine 208.1 (2011) : 195-212.
Version
Final published version
Abstract
NF-κB is an integral component of the immune response to Toxoplasma gondii. Although evidence exists that T. gondii can directly modulate the NF-κB pathway, the parasite-derived effectors involved are unknown. We determined that type II strains of T. gondii activate more NF-κB than type I or type III strains, and using forward genetics we found that this difference is a result of the polymorphic protein GRA15, a novel dense granule protein which T. gondii secretes into the host cell upon invasion. A GRA15-deficient type II strain has a severe defect in both NF-κB nuclear translocation and NF-κB–mediated transcription. Furthermore, human cells expressing type II GRA15 also activate NF-κB, demonstrating that GRA15 alone is sufficient for NF-κB activation. Along with the rhoptry protein ROP16, GRA15 is responsible for a large part of the strain differences in the induction of IL-12 secretion by infected mouse macrophages. In vivo bioluminescent imaging showed that a GRA15-deficient type II strain grows faster compared with wild-type, most likely through its reduced induction of IFN-γ. These results show for the first time that a dense granule protein can modulate host signaling pathways, and dense granule proteins can therefore join rhoptry proteins in T. gondii’s host cell–modifying arsenal.
MIT Department
Massachusetts Institute of Technology. Department of Biology
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Creative Commons Attribution-Non-Commercial-Share Alike 3.0
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DOI of Published Version
https://doi.org/10.1084/jem.20100717
