A model system to study the tumor suppressor APC

研究肿瘤抑制因子APC的模型系统

• 批准号: 7524181
• 负责人: Mark A. Peifer
• 金额: $ 25.64万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7524181
• 关键词: APC2 gene; Actins; Address; Adenomatous Polyposis Coli; Adenomatous Polyposis Coli Protein; Adult; Affect; Alleles; Animals; Armadillo Repeat; Binding; Biochemical; Biological; Biological Models; Brain; Cell Communication; Cells; Characteristics; Chromosomal Instability; Chromosome Segregation; Colon; Colon Carcinoma; Colonic Neoplasms; Complex; Cytoskeleton; Development; Dominant-Negative Mutation; Drosophila genus; Embryonic Development; Employee Strikes; Family; Family member; Funding; Genetic; Genus Cola; Human; Inherited; Localized; Maintenance; Malignant Neoplasms; Mammals; Mediating; Microtubules; Modeling; Mutate; Noise; Other Finding; Pathway interactions; Phenotype; Phosphorylation; Play; Plus End of the Microtubule; Population; Process; Protein Family; Proteins; Public Health; Regulation; Role; Role playing therapy; Scaffolding Protein; Series; Set protein; Shapes; Signal Transduction; Signal Transduction Pathway; Stem cells; Structure; Tertiary Protein Structure; Testing; Time; Tissues; Tumor Suppressor Proteins; Undifferentiated; Upper arm; Work; Wound Healing; bone; cell behavior; cell cortex; fascinate; fly; human disease; interest; loss of function; malformation; mutant; neuronal cell body; protein protein interaction; tool; tumor; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): Several key signal transduction pathways play critical roles in animal development, and also are inappropriately activated in cancer. Among these is the Wnt pathway. Its role in human cancer was first identified through the tumor suppressor Adenomatous polyposis coli (APC), mutated in most colon cancers. We now know that APC is a critical negative regulator of Wnt signaling. APC is part of a multiprotein "destruction complex" targeting the key Wnt effector _catenin for phosphorylation and eventual proteasomal destruction. Understanding APC function is essential both to understanding how Wnt signaling shapes normal development and how its inappropriate activation contributes to cancer. In addition to its role in Wnt regulation, APC also plays roles in cytoskeletal regulation. Diverse cytoskeletal functions have been ascribed to APC. Among these is a proposed role in chromosome instability in APC mutant tumors, via effects on chromosome segregation. We established a model system to study APC function in Wnt signaling and cytoskeletal regulation during normal development and to model how its inactivation leads to cancer. We use the fruit fly Drosophila, making use of the powerful combination of genetic, cell biological and biochemical tools available in flies. Both mammals and Drosophila have two APC family members, which all share a core set of protein domains but which differ at their N- and C-termini. In the past funding period, we addressed several key questions in the field. First, we discovered that the two fly APC family members act redundantly in Wnt signaling in many tissues, despite their divergent structures and striking differences in intracellular localization. Second, we generated a null allele of APC2. Using existing null alleles of APC1, this allowed us to create, for the first time, both tissues and whole animals null for both APC family members, revealing the null phenotypes of APC function in both Wnt and cytoskeletal regulation. We also generated a series of new APC2 alleles; among other findings these revealed that the truncated APC proteins characteristic of colon tumors are reduced for Wnt regulation but not null, supporting the "just right" hypothesis. They also revealed that these truncated proteins have dominant negative effects on the cytoskeleton but not in Wnt signaling. Despite the great interest in APC, key questions remain regarding its roles in the destruction complex and cytoskeletal regulation. We propose 3 Specific Aims, each addressing key questions: Aim 1: Define the mechanism(s) of action of APC proteins in the destruction complex. Aim 2: Determine how APC structure influences the assembly and activity of the destruction complex and regulates _catenin transfer to the E3 ligase Aim 3: Explore mechanisms by which APC family proteins regulate the cytoskeleton PUBLIC HEALTH RELEVANCE The body's cells communicate with one another during normal development of an embryo, and in adult tissues to regulate tissue maintenance and repair wounds. Altered cell communication underlies several common cancers including colon cancer, while loss of cell communication causes some forms of congenital bone malformation. We have developed a model system to explore how the tumor suppressor APC normally regulates cell communication and cell behavior, to allow better understanding of what goes wrong in human disease.

描述（由申请人提供）：几种关键信号转导途径在动物发育中起关键作用，并且在癌症中也不当激活。其中是WNT途径。它在人类癌症中的作用首先是通过大多数结肠癌突变的肿瘤抑制腺瘤性息肉病（APC）鉴定的。我们现在知道APC是WNT信号的关键负调节剂。 APC是针对磷酸化和最终蛋白酶体破坏的密钥WNT效应子_Catenin的多蛋白“破坏复合物”的一部分。了解APC功能对于理解Wnt信号如何塑造正常发育以及其不适当的激活对癌症至关重要。除了其在WNT调节中的作用外，APC还在细胞骨架调节中起着作用。多种细胞骨架功能已归因于APC。其中是通过对染色体分离的影响在APC突变肿瘤中染色体不稳定性中提出的作用。我们建立了一个模型系统，以在正常发育过程中研究Wnt信号传导和细胞骨架调节中的APC功能，并模拟其失活如何导致癌症。我们使用果蝇果蝇，利用果蝇可用的遗传，细胞生物学和生化工具的强大组合。哺乳动物和果蝇都有两个APC家族成员，它们都共享一组核心蛋白质领域，但在N-和C-termini上有所不同。在过去的资金期间，我们解决了该领域的几个关键问题。首先，我们发现两个Fly APC家族成员在许多组织中的Wnt信号传导中有冗余的作用，尽管它们的结构有分歧，并且在细胞内定位方面存在明显的差异。其次，我们生成了APC2的无效等位基因。使用APC1的现有无效等位基因，这使我们能够首次为两个APC家族成员创建组织和全动物无效，从而揭示了Wnt和细胞骨架调节中APC功能的无效表型。我们还生成了一系列新的APC2等位基因。除其他发现外，这些发现表明，对于Wnt调节而言，截短的APC蛋白特征降低了，但不能支持“正义”假设。他们还揭示了这些截短的蛋白质对细胞骨架具有显着的负面影响，但在Wnt信号传导中却没有主导。尽管对APC非常感兴趣，但其在破坏复合物和细胞骨架调节中的作用仍然存在。我们提出了3个具体目标，每个目标都解决了关键问题：目标1：定义APC蛋白在破坏复合物中的作用机制。目标2：确定APC结构如何影响破坏复合物的组装和活性，并调节_CATENIN转移到E3连接酶目标3：探索APC家族蛋白通过该机制调节细胞骨架公共卫生相关性的机制，在正常的胚胎生长过程中，人体在胚胎组织的正常发育过程中相互通信，以调节成人组织和修复组织和修复组织的伤害。细胞通信的改变是包括结肠癌在内的几种常见癌症的基础，而细胞通信的丧失会导致某些形式的先天性骨畸形。我们已经开发了一个模型系统，以探索抑制肿瘤APC通常如何调节细胞通信和细胞行为，以更好地了解人类疾病中出了什么问题。