Cutting edge: autoantigen Ro52 is an interferon inducible E3 ligase that ubiquitinates IRF-8 and enhances cytokine expression in macrophages.
IFN regulatory factor (IRF)-8 is a transcription factor important for the development and function of macrophages. It plays a critical role in the induction of cytokine genes, including IL-12p40. Immunopurification and mass spectrometry analysis found that IRF-8 interacted with Ro52 in murine macrophages upon IFN-gamma and TLR stimulation. Ro52 is ... an IFN-inducible protein of the tripartite motif (TRIM) family and is an autoantigen present in patients with Sjoegren's syndrome and systemic lupus erythematosus. Ro52 has a RING motif and is capable of ubiquitinating itself. We show that IRF-8 is ubiquitinated by Ro52 both in vivo and in vitro. Ectopic expression of Ro52 enhanced IL-12p40 expression in IFN-gamma/TLR-stimulated macrophages in an IRF-8-dependent manner. Together, Ro52 is an E3 ligase for IRF-8 that acts in a non-degradation pathway of ubiquitination, and contributes to the elicitation of innate immunity in macrophages.
Mesh Terms:
Animals, Autoantigens, Cell Line, Cytokines, Immunity, Innate, Interferon Regulatory Factors, Interferon-gamma, Macrophage Activation, Macrophages, Mice, Protein Structure, Tertiary, Ribonucleoproteins, Signal Transduction, Toll-Like Receptors, Ubiquitin, Ubiquitin-Protein Ligases, Up-Regulation
Animals, Autoantigens, Cell Line, Cytokines, Immunity, Innate, Interferon Regulatory Factors, Interferon-gamma, Macrophage Activation, Macrophages, Mice, Protein Structure, Tertiary, Ribonucleoproteins, Signal Transduction, Toll-Like Receptors, Ubiquitin, Ubiquitin-Protein Ligases, Up-Regulation
J. Immunol.
Date: Jul. 01, 2007
PubMed ID: 17579016
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