School of Life Science and Technology, ShanghaiTech University, Shanghai, PR China.
CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, PR China.
Nat Commun. 2021 Mar 12;12(1):1627. doi: 10.1038/s41467-021-21881-2.
RIPK3 amyloid complex plays crucial roles during TNF-induced necroptosis and in response to immune defense in both human and mouse. Here, we have structurally characterized mouse RIPK3 homogeneous self-assembly using solid-state NMR, revealing a well-ordered N-shaped amyloid core structure featured with 3 parallel in-register β-sheets. This structure differs from previously published human RIPK1/RIPK3 hetero-amyloid complex structure, which adopted a serpentine fold. Functional studies indicate both RIPK1-RIPK3 binding and RIPK3 amyloid formation are essential but not sufficient for TNF-induced necroptosis. The structural integrity of RIPK3 fibril with three β-strands is necessary for signaling. Molecular dynamics simulations with a mouse RIPK1/RIPK3 model indicate that the hetero-amyloid is less stable when adopting the RIPK3 fibril conformation, suggesting a structural transformation of RIPK3 from RIPK1-RIPK3 binding to RIPK3 amyloid formation. This structural transformation would provide the missing link connecting RIPK1-RIPK3 binding to RIPK3 homo-oligomer formation in the signal transduction.
RIPK3 淀粉样复合物在 TNF 诱导的细胞坏死和人类及小鼠免疫防御中发挥关键作用。在此，我们使用固态 NMR 对小鼠 RIPK3 同型寡聚体进行了结构表征，揭示了一种有序的 N 型淀粉样核心结构，具有 3 个平行的顺序 β-折叠。该结构与先前发表的人源 RIPK1/RIPK3 异源淀粉样复合物结构不同，后者采用蛇形折叠。功能研究表明，RIPK1-RIPK3 结合和 RIPK3 淀粉样形成对于 TNF 诱导的细胞坏死是必需的，但不是充分的。具有三个 β-链的 RIPK3 纤维的结构完整性对于信号转导是必要的。使用小鼠 RIPK1/RIPK3 模型的分子动力学模拟表明，异源淀粉样采用 RIPK3 纤维构象时不太稳定，这表明 RIPK3 从 RIPK1-RIPK3 结合到 RIPK3 淀粉样形成的结构转换。这种结构转换将提供连接 RIPK1-RIPK3 结合到信号转导中 RIPK3 同源寡聚体形成的缺失环节。
