Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA.
QB3, University of California, Berkeley, CA 94720, USA.
Science. 2020 Dec 4;370(6521). doi: 10.1126/science.abd9993.
Plants and animals detect pathogen infection using intracellular nucleotide-binding leucine-rich repeat receptors (NLRs) that directly or indirectly recognize pathogen effectors and activate an immune response. How effector sensing triggers NLR activation remains poorly understood. Here we describe the 3.8-angstrom-resolution cryo-electron microscopy structure of the activated ROQ1 (recognition of XopQ 1), an NLR native to with a Toll-like interleukin-1 receptor (TIR) domain bound to the effector XopQ ( outer protein Q). ROQ1 directly binds to both the predicted active site and surface residues of XopQ while forming a tetrameric resistosome that brings together the TIR domains for downstream immune signaling. Our results suggest a mechanism for the direct recognition of effectors by NLRs leading to the oligomerization-dependent activation of a plant resistosome and signaling by the TIR domain.
动植物利用细胞内核苷酸结合富含亮氨酸重复受体（NLRs）来检测病原体感染，这些受体直接或间接地识别病原体效应子并激活免疫反应。效应子感知如何触发 NLR 激活仍知之甚少。在这里，我们描述了激活的 ROQ1（XopQ1 的识别）的 3.8 埃分辨率冷冻电子显微镜结构，ROQ1 是一种天然存在于 的 NLR，具有 Toll 样白细胞介素-1 受体（TIR）结构域与效应子 XopQ（外蛋白 Q）结合。ROQ1 直接结合 XopQ 的预测活性位点和表面残基，同时形成一个四聚体抵抗体，将 TIR 结构域聚集在一起，进行下游免疫信号转导。我们的结果表明，NLR 直接识别效应子的机制导致了植物抵抗体的寡聚依赖性激活和 TIR 结构域的信号转导。
