Nuclear transport receptor KA120 regulates molecular condensation of MAC3 to coordinate plant immune activation
Nuclear transport receptor KA120 regulates molecular condensation of MAC3 to coordinate plant immune activation
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DOI：
10.1016/j.chom.2023.08.015
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发表时间：
2023-10-11
影响因子：
30.3
通讯作者：
Gu，Yangnan
中科院分区：
文献类型：
--
作者：
Jia，Min;Chen，Xuanyi;Gu，Yangnan
核细胞质交换对真核生物的生命至关重要，它是由核细胞转运受体超家族的核细胞蛋白介导的。然而，植物核细胞蛋白的功能和载货谱在很大程度上是不清楚的。在这里，我们报告了基于接近标记的KA120体内底物的蛋白质组学分析，KA120是一种抑制拟南芥自身免疫诱导所需的核蛋白-β。我们鉴定了mos4相关复合体（MAC）的多个组分，这是一种保守的剪接调节蛋白复合体。令人惊讶的是，我们发现KA120并不影响MAC蛋白的核胞质分布，而是阻止其蛋白在细胞核内的凝聚。此外，我们证明了MAC凝结是由病原体感染强烈诱导的，这足以激活防御基因表达，可能是通过相变隔离负免疫调节因子。我们的研究揭示了一种植物核丝蛋白的非规范伴随活性，它可以调节进化上保守的剪接调节复合体的核凝聚，以协调植物的免疫激活。
The nucleocytoplasmic exchange is of fundamental importance to eukaryotic life and is mediated by karyopherins, a superfamily of nuclear transport receptors. However, the function and cargo spectrum of plant karyopherins are largely obscure. Here, we report proximity-labeling-based proteomic profiling ofin vivosubstrates of KA120, a karyopherin-β required for suppressing autoimmune induction inArabidopsis. We identify multiple components of the MOS4-associated complex (MAC), a conserved splicing regulatory protein complex. Surprisingly, we find that KA120 does not affect the nucleocytoplasmic distribution of MAC proteins but rather prevents their protein condensation in the nucleus. Furthermore, we demonstrate that MAC condensation is robustly induced by pathogen infection, which is sufficient to activate defense gene expression, possibly by sequestrating negative immune regulators via phase transition. Our study reveals a noncanonical chaperoning activity of a plant karyopherin, which modulates the nuclear condensation of an evolutionarily conserved splicing regulatory complex to coordinate plant immune activation.