Toxoplasma GRA15 limits parasite growth in IFNγ-activated fibroblasts through TRAF ubiquitin ligases

Debanjan Mukhopadhyay, Lamba Omar Sangaré, Laurence Braun, Mohamed Ali Hakimi, Jeroen P.J. Saeij

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


The protozoan parasite Toxoplasma gondii lives inside a vacuole in the host cytosol where it is protected from host cytoplasmic innate immune responses. However, IFNγ-dependent cell-autonomous immunity can destroy the vacuole and the parasite inside. Toxoplasma strain differences in susceptibility to human IFNγ exist, but the Toxoplasma effector(s) that determine these differences are unknown. We show that in human primary fibroblasts, the polymorphic Toxoplasma-secreted effector GRA15 mediates the recruitment of ubiquitin ligases, including TRAF2 and TRAF6, to the vacuole membrane, which enhances recruitment of ubiquitin receptors (p62/NDP52) and ubiquitin-like molecules (LC3B, GABARAP). This ultimately leads to lysosomal degradation of the vacuole. In murine fibroblasts, GRA15-mediated TRAF6 recruitment mediates the recruitment of immunity-related GTPases and destruction of the vacuole. Thus, we have identified how the Toxoplasma effector GRA15 affects cell-autonomous immunity in human and murine cells.

Original languageEnglish (US)
Article numbere103758
JournalEMBO Journal
Issue number10
StatePublished - May 18 2020


  • GRA15
  • IFNγ
  • p62
  • Toxoplasma
  • TRAF6

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)


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