Ran & Energy Requirements for Nuclear Protein Import

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• 批准号: 6780397
• 负责人: KIMON C KANELAKIS
• 金额: $ 4.38万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2005-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6780397
• 关键词: affinity chromatography; cell nucleus; confocal scanning microscopy; cytoplasm; enzyme linked immunosorbent assay; guanosinetriphosphatases; intracellular transport; membrane transport proteins; nuclear membrane; nuclear proteins; nuclear receptors; protein transport; western blottings

DESCRIPTION (provided by applicant): Trafficking of macromolecules between the nucleus and cytoplasm is mediated by nucleocytoplasmic shuttling receptors, which translocate cargo through the nuclear pore complex (NPC) by binding to a series of nucleoporins. The small GTPase Ran plays a critical role in nuclear import by modulating the interaction of cargo with these transport receptors. Several groups have shown that in vitro nuclear import of certain small cargoes by the importin alpha/importin beta and transportin receptor pathways can occur in the absence of Ran and/or NTP hydrolysis. By contrast, recent work from the Gerace lab has shown that both Ran and hydrolyzable GTP are needed for the efficient import of certain large cargoes by these pathways. To accommodate these findings, a model is proposed where the requirements for Ran and energy in nuclear import of a cargo-receptor complex is governed by the diffusion rate of the complex and by the affinity of the complex for nucleoporins. The aims of this proposal are directed at testing this model in detail by examining the effects of cargo size and affinity of the transport complex for nucleoporins in the importin alpha/importin beta, snurportin/importin beta, and the transportin receptor pathways. These studies are expected to provide insight on the basic mechanism of translocation through the NPC and the Ran requirement in this process. This is a fundamental process that is important for the biology of the cell in a wide range of normal conditions and may be altered in certain pathological states.

描述（由申请人提供）： 细胞核和细胞质之间大分子的运输是由核细胞质穿梭受体介导的，该受体通过与一系列核孔蛋白结合，通过核孔复合体 (NPC) 转运货物。小 GTPase Ran 通过调节货物与这些转运受体的相互作用，在核输入中发挥着关键作用。几个小组已经表明，在没有 Ran 和/或 NTP 水解的情况下，可以通过输入蛋白 α/输入蛋白 β 和转运蛋白受体途径进行某些小货物的体外核输入。相比之下，Gerace 实验室最近的工作表明，通过这些途径有效进口某些大型货物需要 Ran 和可水解 GTP。为了适应这些发现，提出了一个模型，其中货物-受体复合物的核输入对 Ran 和能量的需求由复合物的扩散速率和复合物对核孔蛋白的亲和力控制。该提案的目的是通过检查货物大小和转运复合物对输入蛋白 α/输入蛋白 β、snurportin/输入蛋白 β 和转运蛋白受体途径中核孔蛋白的亲和力的影响来详细测试该模型。这些研究有望深入了解 NPC 易位的基本机制以及该过程中的 Ran 要求。这是一个基本过程，对于多种正常条件下的细胞生物学非常重要，并且在某些病理状态下可能会发生改变。