Phosphorylation-Regulated Activation of the Arabidopsis RISRS1-R/RPS4 Immune Receptor Complex Reveals Two Distinct Effector Recognition Mechanisms
Phosphorylation-Regulated Activation of the Arabidopsis RISRS1-R/RPS4 Immune Receptor Complex Reveals Two Distinct Effector Recognition Mechanisms
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DOI：
10.1016/j.chom.2020.03.008
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发表时间：
2020-05-13
影响因子：
30.3
通讯作者：
Jones, Jonathan D. G.
中科院分区：
文献类型：
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作者：
Guo, Hailong;Ahn, Hee-Kyung;Jones, Jonathan D. G.
拟南芥免疫受体 RPS4 和 RRS1 相互作用，共同赋予对细菌效应子的反应性。 RRS1-R 等位基因与 RPS4 一起响应 AvrRps4 和 PopP2，而 RRS1-S 仅响应 AvrRps4。在这里，我们发现 RRS1-R 的 C 末端被磷酸化，但 RRS1-S 没有被磷酸化。 WRKY 结构域中 Thr1214 的磷酸化使 RRS1-R 维持在非活性状态，并抑制 PopP2 对 RRS1-R 的乙酰化。 PopP2 反过来在同一位点催化 O-乙酰化，从而阻止其磷酸化。 PopP2 需要其他位点的磷酸化，但 AvrRps4 不需要，并促进 RRS1 的 C 末端与其 TIR 结构域的相互作用。 RRS1-R 或 RRS1-S 的去抑制涉及效应器触发的 TIR 结构域和 C 末端之间的接近。这些结构域之间的这种效应子促进的相互作用缓解了 TIRRRS1 对 TIRRPS4 的抑制。我们的数据揭示了 RRS1 内效应器触发和磷酸化调节的构象变化，导致 PopP2 和 AvrRps4 对复合物产生不同的去抑制模式。
The Arabidopsis immune receptors RPS4 and RRS1 interact to co-confer responsiveness to bacterial effectors. The RRS1-R allele, with RPS4, responds to AvrRps4 and PopP2, whereas RRS1-S responds only to AvrRps4. Here, we show that the C terminus of RRS1-R but not RRS1-S is phosphorylated. Phosphorylation at Thr1214 in the WRKY domain maintains RRS1-R in its inactive state and also inhibits acetylation of RRS1-R by PopP2. PopP2 in turn catalyzes O-acetylation at the same site, thereby preventing its phosphorylation. Phosphorylation at other sites is required for PopP2 but not AvrRps4 responsiveness and facilitates the interaction of RRS1's C terminus with its TIR domain. Derepression of RRS1-R or RRS1-S involves effector-triggered proximity between their TIR domain and C termini. This effector-promoted interaction between these domains relieves inhibition of TIRRPS4 by TIRRRS1. Our data reveal effector-triggered and phosphorylation-regulated conformational changes within RRS1 that results in distinct modes of derepression of the complex by PopP2 and AvrRps4.