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: 7902993
• 负责人: Mark A. Peifer
• 金额: $ 7.27万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7902993
• 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; Human; Inherited; Maintenance; Malignant Neoplasms; Mammals; Mediating; Microtubules; Modeling; Mutate; Noise; Pathway interactions; Phenotype; Phosphorylation; Play; Plus End of the Microtubule; Process; Protein Family; Proteins; Regulation; Role; 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; stem cell population; tool; tumor; ubiquitin-protein ligase

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 Project Narrative 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.

几种关键的信号转导途径在动物发育中起着关键作用， 在癌症中被不适当地激活。其中之一是Wnt途径。它在人类癌症中的作用是 首先通过肿瘤抑制基因大肠腺瘤性息肉病（APC）鉴定， 结肠癌我们现在知道APC是Wnt信号传导的关键负调节因子。APC是一部分 一种多蛋白“破坏复合物”，靶向关键的Wnt效应子连环蛋白磷酸化 最终导致蛋白酶体的破坏了解APC功能对于以下两个方面都至关重要： 了解Wnt信号传导如何影响正常发育及其不适当激活 会导致癌症除了在Wnt调节中发挥作用外，APC还在细胞骨架中发挥作用 调控APC具有多种细胞骨架功能。其中一项提议是， 通过影响染色体分离，在APC突变型肿瘤的染色体不稳定性中发挥作用。 我们建立了一个模型系统来研究APC在Wnt信号和细胞骨架调节中的作用 并模拟其失活如何导致癌症。我们用果蝇 果蝇，利用遗传学，细胞生物学和生物化学工具的强大组合 在苍蝇中可用。哺乳动物和果蝇都有两个APC家族成员，它们都共享一个 蛋白质结构域的核心组，但在它们的N-和C-末端不同。在过去的一段时间里，我们 解决了该领域的几个关键问题。首先，我们发现两个飞行APC家庭 成员在许多组织中在Wnt信号传导中起冗余作用，尽管它们的结构不同， 细胞内定位的显著差异。其次，我们产生了APC 2的无效等位基因。使用 APC 1的现有无效等位基因，这使我们能够创建，第一次，组织和整体， 动物无效的两个APC家族成员，揭示空表型的APC功能，在两个 Wnt与细胞骨架调控。我们还产生了一系列新的APC 2等位基因; 这些发现揭示了结肠肿瘤特征性的截短APC蛋白减少， 对于Wnt调节，但不是空的，支持“刚好”假设。他们还透露， 截短的蛋白质对细胞骨架具有显性负效应，但对Wnt信号传导没有。 尽管人们对装甲运兵车很感兴趣，但关于它在销毁中的作用， 复杂和细胞骨架调节。我们提出了三个具体目标，每个目标都涉及关键问题： 目的1：确定APC蛋白在破坏复合物中的作用机制。 目标2：确定装甲运兵车的结构如何影响销毁的组装和活动 复合物并调节连环蛋白转移到E3连接酶 目的3：探索APC家族蛋白调节细胞骨架的机制 身体的细胞在正常发育过程中相互交流， 胚胎中，并在成人组织中调节组织维护和修复伤口。改变 细胞通讯是包括结肠癌在内的几种常见癌症的基础， 细胞通讯的中断会导致某种形式的先天性骨骼畸形。我们有 开发了一个模型系统来探索肿瘤抑制因子APC如何正常调节 细胞通讯和细胞行为，以便更好地了解出了什么问题， 在人类疾病中。