Self protection from anti-viral responses--Ro52 promotes degradation of the transcription factor IRF7 downstream of the viral Toll-Like receptors.
journal contributionposted on 2022-03-14, 15:07 authored by Rowan Higgs, Elisa Lazzari, Claire Wynne, Joan Ni Gabhann-DromgooleJoan Ni Gabhann-Dromgoole, Alexander Espinosa, Marie Wahren-Herlenius, Caroline A. Jefferies
Ro52 is a member of the TRIM family of single-protein E3 ligases and is also a target for autoantibody production in systemic lupus erythematosus and Sjögren's syndrome. We previously demonstrated a novel function of Ro52 in the ubiquitination and proteasomal degradation of IRF3 following TLR3/4 stimulation. We now present evidence that Ro52 has a similar role in regulating the stability and activity of IRF7. Endogenous immunoprecipitation of Ro52-bound proteins revealed that IRF7 associates with Ro52, an effect which increases following TLR7 and TLR9 stimulation, suggesting that Ro52 interacts with IRF7 post-pathogen recognition. Furthermore, we show that Ro52 ubiquitinates IRF7 in a dose-dependent manner, resulting in a decrease in total IRF7 expression and a subsequent decrease in IFN-alpha production. IRF7 stability was increased in bone marrow-derived macrophages from Ro52-deficient mice stimulated with imiquimod or CpG-B, consistent with a role for Ro52 in the negative regulation of IRF7 signalling. Taken together, these results suggest that Ro52-mediated ubiquitination promotes the degradation of IRF7 following TLR7 and TLR9 stimulation. As Ro52 is known to be IFN-inducible, this system constitutes a negative-feedback loop that acts to protect the host from the prolonged activation of the immune response.
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Published CitationHiggs R, Lazzari E, Wynne C, Ní Gabhann J, Espinosa A, Wahren-Herlenius M, Jefferies CA. Self protection from anti-viral responses--Ro52 promotes degradation of the transcription factor IRF7 downstream of the viral Toll-Like receptors. PLoS One. 2010 Jul 26;5(7):e11776.
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