RT Journal Article SR Electronic T1 Toxoplasma GRA15 limits parasite growth in IFNγ-activated fibroblasts through TRAF ubiquitin ligases JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.02.24.963496 DO 10.1101/2020.02.24.963496 A1 Mukhopadhyay, Debanjan A1 Sangaré, Lamba Omar A1 Braun, Laurence A1 Hakimi, Mohamed-Ali A1 Saeij, Jeroen P.J. YR 2020 UL http://biorxiv.org/content/early/2020/02/26/2020.02.24.963496.abstract AB The protozoan parasite Toxoplasma gondii lives inside a vacuole in the host cytoplasm 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.