Structural analysis of TIFA: Insight into TIFA-dependent signal transduction in innate immunity
Structural analysis of TIFA: Insight into TIFA-dependent signal transduction in innate immunity
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DOI：
10.1038/s41598-020-61972-6
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发表时间：
2020-03
影响因子：
4.6
通讯作者：
Teruya Nakamura;C. Hashikawa;Kohtaro Okabe;Yuya Yokote;Mami Chirifu;S. Toma-Fukai;Narushi Nakamura;Mihoko Matsuo;Miho Kamikariya;Yoshinari Okamoto;J. Gohda;T. Akiyama;K. Semba;S. Ikemizu;M. Otsuka;J. Inoue;Y. Yamagata
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文献类型：
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作者：
Teruya Nakamura;C. Hashikawa;Kohtaro Okabe;Yuya Yokote;Mami Chirifu;S. Toma-Fukai;Narushi Nakamura;Mihoko Matsuo;Miho Kamikariya;Yoshinari Okamoto;J. Gohda;T. Akiyama;K. Semba;S. Ikemizu;M. Otsuka;J. Inoue;Y. Yamagata
TRAF相互作用蛋白与叉头相关（FHA）结构域（TIFA），最初被鉴定为TRAF 6的衔接蛋白，最近被证明参与由病原体相关分子模式（PAMP）诱导的先天免疫。ADP-β-D-manno-heptose是一种新发现的PAMP，它与α-激酶1（alpha-kinase 1，ALPK 1）结合，激活其激酶活性，磷酸化TIFA。磷酸化触发TIFA寡聚化并形成随后的TIFA-TRAF 6寡聚复合物，用于TRAF 6的泛素化，最终导致NF-κB活化。然而，TIFA依赖性TRAF 6信号传导的结构基础，特别是TIFA-TRAF 6复合物的寡聚体形成仍然未知。在本研究中，我们确定了小鼠TIFA和两个TIFA突变体的晶体结构-Thr 9突变为Asp或Glu以模拟磷酸化状态-以获得TIFA-TRAF 6复合物寡聚体形成的结构信息。晶体结构显示小鼠TIFA的二聚体形成类似于先前报道的人TIFA的二聚体形成。该二聚体结构与从小角X射线散射分析获得的溶液结构一致。除了结构分析，我们研究了分子组装的TIFA和TIFA-TRAF 6复合物的尺寸排阻色谱法，并提出了一个模型的TIFA-TRAF 6信号复合物。
TRAF-interacting protein with a forkhead-associated (FHA) domain (TIFA), originally identified as an adaptor protein of TRAF6, has recently been shown to be involved in innate immunity, induced by a pathogen-associated molecular pattern (PAMP). ADP-β-D-manno-heptose, a newly identified PAMP, binds to alpha-kinase 1 (ALPK1) and activates its kinase activity to phosphorylate TIFA. Phosphorylation triggers TIFA oligomerisation and formation of a subsequent TIFA–TRAF6 oligomeric complex for ubiquitination of TRAF6, eventually leading to NF-κB activation. However, the structural basis of TIFA-dependent TRAF6 signalling, especially oligomer formation of the TIFA–TRAF6 complex remains unknown. In the present study, we determined the crystal structures of mouse TIFA and two TIFA mutants—Thr9 mutated to either Asp or Glu to mimic the phosphorylation state—to obtain the structural information for oligomer formation of the TIFA–TRAF6 complex. Crystal structures show the dimer formation of mouse TIFA to be similar to that of human TIFA, which was previously reported. This dimeric structure is consistent with the solution structure obtained from small angle X-ray scattering analysis. In addition to the structural analysis, we examined the molecular assembly of TIFA and the TIFA–TRAF6 complex by size-exclusion chromatography, and suggested a model for the TIFA–TRAF6 signalling complex.