Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing 100875, China.
Department of Vegetable Sciences, Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing 100193, China.
Proc Natl Acad Sci U S A. 2024 Jun 18;121(25):e2312415121. doi: 10.1073/pnas.2312415121. Epub 2024 Jun 14.
Plants rely on immune receptor complexes at the cell surface to perceive microbial molecules and transduce these signals into the cell to regulate immunity. Various immune receptors and associated proteins are often dynamically distributed in specific nanodomains on the plasma membrane (PM). However, the exact molecular mechanism and functional relevance of this nanodomain targeting in plant immunity regulation remain largely unknown. By utilizing high spatiotemporal resolution imaging and single-particle tracking analysis, we show that myosin XIK interacts with remorin to recruit and stabilize PM-associated kinase BOTRYTIS-INDUCED KINASE 1 (BIK1) within immune receptor FLAGELLIN SENSING 2 (FLS2)-containing nanodomains. This recruitment facilitates FLS2/BIK1 complex formation, leading to the full activation of BIK1-dependent defense responses upon ligand perception. Collectively, our findings provide compelling evidence that myosin XI functions as a molecular scaffold to enable a spatially confined complex assembly within nanodomains. This ensures the presence of a sufficient quantity of preformed immune receptor complex for efficient signaling transduction from the cell surface.
植物依靠细胞表面的免疫受体复合物来感知微生物分子，并将这些信号转导到细胞内，以调节免疫。各种免疫受体和相关蛋白通常在质膜（PM）上的特定纳米域中动态分布。然而，这种纳米域靶向在植物免疫调节中的确切分子机制和功能相关性在很大程度上仍然未知。通过利用高时空分辨率成像和单粒子跟踪分析，我们表明肌球蛋白 XIK 与 remorin 相互作用，在包含免疫受体 FLAGELLIN SENSING 2（FLS2）的纳米域内募集并稳定 PM 相关激酶 BOTRYTIS-INDUCED KINASE 1（BIK1）。这种募集促进了 FLS2/BIK1 复合物的形成，导致配体感知后 BIK1 依赖性防御反应的完全激活。总之，我们的研究结果提供了令人信服的证据，表明肌球蛋白 XI 作为一种分子支架，能够在纳米域内实现空间受限的复合物组装。这确保了预先形成的免疫受体复合物的数量充足，从而能够从质膜进行有效的信号转导。
