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.

几种关键信号传输途径在动物开发中起关键作用，也是 在癌症中不适当地激活。其中是WNT途径。它在人类癌症中的作用是 首先通过肿瘤抑制腺瘤性息肉病（APC）鉴定，大多数突变 结肠癌。我们现在知道APC是WNT信号的关键负调节剂。 APC是一部分 靶向密钥wnt效应子的多蛋白“破坏复合物”的磷酸化 和最终的蛋白酶体破坏。了解APC功能对 了解Wnt信号如何塑造正常发展以及其不适当的激活 有助于癌症。除了其在WNT调节中的作用外，APC还在细胞骨架中扮演角色 规定。已将各种细胞骨架功能分配给APC。其中是一个建议 通过对染色体分离的影响，在APC突变肿瘤中的染色体不稳定性中的作用。 我们建立了一个模型系统，以研究Wnt信号传导和细胞骨架调节中的APC功能 在正常发育期间，并模拟其失活如何导致癌症。我们使用果蝇 果蝇，利用遗传，细胞生物学和生化工具的强大组合 有苍蝇。哺乳动物和果蝇都有两个APC家庭成员，它们都有一个 蛋白质结构域的核心集，但在其N-和C末端有所不同。在过去的资金期间，我们 在现场解决了几个关键问题。首先，我们发现两个飞行APC家族 成员在许多组织中的Wnt信号中有冗余的作用，呈现其不同的结构和 细胞内定位的差异。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，这使我们能够首次创建组织和整个 APC家族成员的动物无效，揭示了APC功能的无效表型 Wnt和细胞骨架调节。我们还生成了一系列新的APC2等位基因。除其他 这些发现表明，结肠肿瘤的截短的APC蛋白特征会减少 对于Wnt调节而非零，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要影响。 尽管对APC非常感兴趣，但仍然对其在破坏中的作用仍然存在关键问题 复杂和细胞骨架调节。我们提出3个具体目标，每个目标都解决关键问题： 目标1：定义APC蛋白在破坏复合物中的作用机理。 目标2：确定APC结构如何影响破坏的组装和活动 复杂并调节catenin转移到E3连接酶 目标3：探索APC家族蛋白调节细胞骨架项目叙事的机制 在正常发展期间，人体的细胞相互通信 胚胎和成年组织中以调节组织维护和修复伤口。改变 细胞通信是包括结肠癌在内的几种常见癌症的基础，而损失 细胞通信导致某些形式的先天性骨畸形。我们有 开发了一个模型系统，以探讨肿瘤抑制APC通常如何调节的模型系统 细胞通信和细胞行为，以更好地理解出什么问题 在人类疾病中。