Molecular functions of nuclear pore complex proteins in plant defense signal transduction and gene expression

核膜作为基因组的保护隔室边界，为真核细胞控制信号事件和基因表达的特异性和时间提供了重要手段。核孔复合物由核孔蛋白（NUPs）组成，可穿透核膜，并已成为调节植物细胞对微生物病原体攻击反应的战略平台。然而，在植物免疫中，单个核孔蛋白调控核胞质信号传递和基因表达输出的具体分子机制和功能作用尚不全面。本实验室近期的研究表明拟南芥核孔蛋白NUP88、NUP96和NUP160通过不同的分子机制影响植物的免疫应答。NUP96和NUP160都参与细胞核mRNA的输出，对某些防御基因的充分表达至关重要。相反，NUP88选择性地减弱重要防御调节蛋白的核输出，促进其在核质内的积累。因此，我提议两个子项目。其中一个项目将重点研究NUP88在植物免疫中的功能作用。我们将测试NUP88通过调节未知免疫调节蛋白的核浓度选择性调节多种不同的防御信号通路的假设。它们的鉴定和随后在植物防御信号转导中的详细功能表征是本项目的主要目标。另一个项目将研究NUP96和NUP160如何机械地影响特异性免疫应答基因的表达和mRNA输出。我们将研究这两种核孔蛋白控制的mRNA输出途径，并在防御基因表达调控中解决转运无关但与染色质相关的功能。这可能揭示调控植物抗病的新靶点和分子机制，促进未来的可持续粮食安全。

The nuclear envelope acts as a protective compartment boundary for the genome and provides eukaryotic cells with an important means to control the specificity and timing of signaling events and gene expression. Nuclear pore complexes, composed of nucleoporin proteins (NUPs), perforate the nuclear envelope and have emerged as a strategic platform for regulating plant cellular responses to microbial pathogen attack. However, the detailed molecular mechanisms and the functional role of individual nucleoporins in regulating nucleocytoplasmic signal relay and gene expression outputs in plant immunity are far from comprehensive. Recent work in our laboratory shows that the Arabidopsis nucleoporins NUP88, NUP96 and NUP160 affect plant immune responses by different molecular mechanisms. Both NUP96 and NUP160 are involved in nuclear mRNA export and essential for full expression of certain defense genes. In contrast, NUP88 selectively attenuates nuclear export of important defense regulatory proteins to promote their accumulation inside the nucleoplasm. I therefore propose two subprojects. One project will focus on the functional role of NUP88 in plant immunity. We will test the hypothesis that NUP88 selectively modulates multiple distinct defense signaling pathways by regulating nuclear concentrations of unknown immune regulatory proteins. Their identification and subsequent detailed functional characterization in plant defense signal transduction is a major goal of this project. The other project will address how NUP96 and NUP160 mechanistically influence the expression and mRNA export of specific immune response genes. We will investigate which mRNA export pathways are controlled by these two nucleoporins and address transport-independent but chromatin-related functions in the regulation of defense gene expression. This may reveal new targets and molecular mechanisms to modulate plant disease resistance for future sustainable food security.