Cargo sorting during endocytic recycling

内吞回收过程中的货物分类

• 批准号: 7280848
• 负责人: VICTOR W HSU
• 金额: $ 29.87万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7280848
• 关键词: Cargo; sorting; during; endocytic; recycling

DESCRIPTION (provided by applicant): Endocytic recycling is critical for many cellular events, including the recycling of important nutrient receptors, such as the transferrin receptor and the low-density lipoprotein receptor, for reiterative rounds of ligand uptake, and also the redistribution of integrins from the retracting edges to the leading edge of cells to mediate their motility. Despite these many documented important roles, how proteins are sorted during endocytic recycling, a process that critically regulates their function remains poorly understood. In preliminary studies, we have identified ACAP1 to function in the sorting of cargo proteins that exemplify constitutive and regulated recycling at the recycling endosome, with its phosphorylation providing an explanation for how it is able to participate in both processes. Moreover, we have found that overexpression of ACAP1 induces the coating of endosomes. Thus, in Aim 1, we will provide a more definitive test for whether ACAP1 functions as a coat protein using a reconstitution system that generates transport carriers from the recycling endosome, followed by approaches which will either prove that ACAP1 alone functions as a coat protein or that it functions in conjunction with other proteins as part of coat complex. In Aim 2, because the critical nexus in regulated transport involves the signaling process interfacing with the transport process, we will identify kinase(s) predicted to directly phosphorylate ACAP1. In Aim 3, as we have identified sorting signals recognized by ACAP1 for constitutive recycling, we will also identify sorting signal(s) recognized by ACAP1 for regulated recycling, using integrin beta1 as the model system. This finding will then enable us to further elucidate how ACAP1 is able to participate in both constitutive and regulated recycling. Moreover, the identification of recycling sorting signal(s) in integrin beta1 will allow us to test more definitively whether integrin recycling plays a critical role in cell migration, and thereby demonstrating that a better understanding of endocytic recycling has important implications to understanding other cellular events.

描述（由申请人提供）：内吞再循环对于许多细胞事件至关重要，包括重要营养受体的再循环，例如转铁蛋白受体和低密度脂蛋白受体，用于重复轮次的配体摄取，以及整合素从细胞的回缩边缘到前缘的重新分配以介导其运动。尽管有许多记载的重要作用，但蛋白质在内吞回收过程中如何分类，这一严格调节其功能的过程仍然知之甚少。在初步研究中，我们已经确定 ACAP1 在货物蛋白的分选中发挥作用，这些蛋白体现了回收内体的组成型和调节性回收，其磷酸化为其如何能够参与这两个过程提供了解释。此外，我们发现 ACAP1 的过度表达会诱导内体的涂层。因此，在目标 1 中，我们将使用从回收内体生成转运载体的重构系统，提供更明确的测试来确定 ACAP1 是否作为外壳蛋白发挥作用，然后采用证明 ACAP1 单独发挥作用的方法。 外壳蛋白或它作为外壳复合物的一部分与其他蛋白质一起发挥作用。在目标 2 中，由于调节运输中的关键关系涉及与运输过程相连接的信号传导过程，因此我们将鉴定预计可直接磷酸化 ACAP1 的激酶。在目标 3 中，由于我们已经确定了 ACAP1 识别的用于本构回收的分选信号，我们还将使用整合素 beta1 作为模型系统来识别 ACAP1 识别的用于调节回收的分选信号。这一发现将使我们能够进一步阐明 ACAP1 如何能够参与本构回收和调节回收。此外，整合素β1中回收分选信号的识别将使我们能够更明确地测试整合素回收是否在细胞迁移中发挥关键作用，从而证明更好地理解内吞回收对于理解其他细胞事件具有重要意义。