ARF regulators in endocytic transport

内吞转运中的 ARF 调节因子

• 批准号: 8197831
• 负责人: VICTOR W HSU
• 金额: $ 38.88万
• 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 2013-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8197831
• 关键词: ADP-Ribosylation Factors; ARFGAP1; Binding; Biochemical; Bypass; Capsid Proteins; Cardiovascular system; Cell surface; Cells; Clathrin; Coat Protein Complex I; Complex; Coupled; Coupling; Crystallization; Defect; Disease; Endocytosis; Event; Funding; GTPase-Activating Proteins; Glucose Transporter; Goals; Guanine Nucleotide Exchange Factors; Immunologics; In Transferrin; In Vitro; Insulin; Insulin Signaling Pathway; Investigation; Lead; Link; Membrane; Molecular Conformation; Monomeric GTP-Binding Proteins; N Domain; Neurologic; Non-Insulin-Dependent Diabetes Mellitus; Oncogenic; Pathogenesis; Pathway interactions; Peptides; Phosphorylation; Process; Protein Kinase; Recycling; Role; Signal Transduction; Sorting - Cell Movement; Structure; System; Tertiary Protein Structure; Transcription Factor AP-2 Alpha; Transferrin Receptor; Vesicle; blood glucose regulation; human disease; in vivo; insight; novel; protein distribution; protein function; protein transport; public health relevance

DESCRIPTION (provided by applicant): ADP-Ribosylation Factors (ARFs) regulate coat proteins, which act as the core cellular machinery in coupling vesicle formation and cargo sorting for vesicular transport. The ARF small GTPases are, in turn, regulated by guanine nucleotide exchange factors (GEFs) that catalyze ARF activation and GTPase-activating proteins (GAPs) that catalyze ARF deactivation. In the last funding period, we have been studying how three ARF regulators act in endocytic transport. First, we have identified an ARF GAP, known as ACAP1, to act as the core adaptor in a novel clathrin coat complex for endocytic recycling. We have also found that ACAP1 participates in both constitutive and regulated recycling, with its cargo binding explaining how both types of transport can be accomplished. Thus, we propose to further elucidate how ACAP1 acts in cargo sorting by taking combined biochemical and structural approaches. Second, we have identified Grp1 as the GEF that acts on ARF6 for the endocytic recycling of the glucose transporter type 4 (glut4), a process that is regulated by insulin. Thus, we propose to take combined morphologic and biochemical approaches to elucidate how this GEF may be targeted by insulin-induced signaling that regulates glut4 recycling. Third, we have found that ARFGAP1 is required for a subset of clathrin AP2-dependent transport, as defined by the endocytosis of transferrin receptor. Thus, we will further elucidate this role, examining how ARFGAP1 participates in cargo sorting and vesicle formation and also interrogating the role of its GAP activity. We anticipate that these results will shed key insights into mechanisms of endocytosis and recycling. Moreover, because defects in mechanisms that govern these transport pathways can cause and/or contribute to cardiovascular, immunologic, neurologic and oncogenic diseases, we further anticipate that our results will have broad ramifications to understanding and treating human diseases. PUBLIC HEALTH RELEVANCE: The function of proteins is critically regulated by their localization. This localization is achieved in part by transport pathways that act as highways within the cell. We propose to understand how key components of these pathways function in regulating the distribution of proteins on the cell surface. This understanding will be broadly applicable to understanding human diseases, as many are now appreciated to arise because of defects in protein transport within the cell.

描述（由申请人提供）：ADP-核糖基化因子（ARF）调节外壳蛋白，其作为耦合囊泡形成和囊泡运输的货物分选的核心细胞机制。 ARF 小 GTP 酶依次受催化 ARF 激活的鸟嘌呤核苷酸交换因子 (GEF) 和催化 ARF 失活的 GTP 酶激活蛋白 (GAP) 调节。在上一个资助期间，我们一直在研究三种 ARF 调节剂在内吞运输中的作用。首先，我们确定了 ARF GAP（称为 ACAP1），作为新型网格蛋白外壳复合物中的核心接头，用于内吞回收。我们还发现 ACAP1 参与本构回收和监管回收，其货物绑定解释了如何完成这两种类型的运输。因此，我们建议通过结合生化和结构方法进一步阐明 ACAP1 在货物分拣中的作用。其次，我们已经确定 Grp1 是 GEF，它作用于 ARF6，促进 4 型葡萄糖转运蛋白 (glut4) 的内吞再循环，这是一个受胰岛素调节的过程。因此，我们建议采用形态学和生物化学相结合的方法来阐明这种 GEF 如何成为调节 glut4 循环的胰岛素诱导信号的靶标。第三，我们发现 ARFGAP1 是网格蛋白 AP2 依赖性转运子集所必需的，如转铁蛋白受体的内吞作用所定义的。因此，我们将进一步阐明这一作用，研究 ARFGAP1 如何参与货物分选和囊泡形成，并探讨其 GAP 活性的作用。我们预计这些结果将为内吞作用和回收机制提供重要见解。此外，由于控制这些转运途径的机制缺陷可能导致和/或促成心血管、免疫、神经和致癌疾病，我们进一步预计我们的结果将对理解和治疗人类疾病产生广泛的影响。 公共健康相关性：蛋白质的功能受到其定位的严格调节。这种定位部分是通过充当细胞内高速公路的运输路径来实现的。我们建议了解这些途径的关键组成部分如何在调节细胞表面蛋白质的分布方面发挥作用。这种理解将广泛适用于理解人类疾病，因为现在认为许多疾病是由于细胞内蛋白质运输的缺陷而产生的。