Regulating cell fate and shaping the body plan during morphogenesis and their alteration during oncogenesis

 描述(申请人提供)：在过去的23年里，我们的实验室一直专注于生物学的核心问题之一--单细胞受精卵如何自我组装成动物的复杂身体计划？本文从连接蛋白在细胞黏附和Wnt信号转导中的双重功能入手，将研究集中在两个不同的领域。在我们的第一个项目中，我们探索了细胞如何在形态发生期间利用细胞-细胞相互作用来改变形状、移动和组装极化组织并在组织动态平衡期间保持这些组织，以及细胞如何整合复杂的肌动蛋白调控工具箱中的不同工具来创建不同的肌动蛋白结构。我们在果蝇中探索这一点，使用高度多学科的方法，最近扩大到包括在培养的哺乳动物细胞中的平行研究。我们关注的蛋白质在哺乳动物发育和癌症转移中起着关键作用。我们目前的努力探索了该领域的两个关键问题。首先，我们将确定细胞将细胞间连接连接到肌动蛋白细胞骨架以允许细胞形状改变而不破坏上皮完整性的机制。我们假设细胞使用不同的连接子和连接架构来驱动不同的密钥 细胞形状改变或迁移事件。其次，我们将建立在单个肌动蛋白调节因子生化功能的现有知识基础上，以定义细胞如何整合这些功能以创建正常发育所需的多样化肌动蛋白结构，以及上游信号通路如何塑造这种整合。在我们的第二个项目中，我们使用Wnt信号作为模型，探索细胞如何选择和维持命运。WNT信号实际上塑造了每个器官系统，在许多组织的动态平衡中发挥着关键作用，并在几种常见形式的癌症中被不适当地激活，包括结肠癌，这是癌症死亡的第二大原因。在过去的十年里，我们专注于肿瘤抑制因子腺瘤性息肉病结肠(APC)，它是Wnt信号的关键负调控因子，在80%的结肠癌中发生突变。APC还在调节细胞骨架方面发挥Wnt不依赖的作用，从而促进高保真的染色体分离，这在癌症中也是被破坏的。我们的长期目标是确定APC及其蛋白质伙伴在正常发育和动态平衡过程中如何调节Wnt信号和细胞骨架，以及在癌症中这是如何出错的。在下一个供资期间，我们将解决实地的两个关键问题。首先，我们将确定多蛋白破坏复合体靶向Wnt效应器-连环蛋白进行磷酸化，将其转移到E3连接酶以最终破坏蛋白酶体的机制，以及Wnt信号如何调节其活性。这是一个调节蛋白质稳定性如何调节的范例。 细胞信号。其次，我们将探索基因组稳定性的调节，定义APC如何作为细胞骨架调节器来确保有丝分裂的保真度，并定义缓冲其丢失的机制。更广泛地说，我们将使用我们新开发的小头畸形果蝇模型，确定如何在不同的组织中重新绘制有丝分裂调节和检查点的遗传电路，以满足不同的需求，对比上皮细胞和神经前体细胞。

 DESCRIPTION (provided by applicant): For the past 23 years, our lab has focused on one of biology's central questions--how does the single cell zygote self-assemble itself into the complex body plan of an animal? Beginning with the dual functions of ß- catenin in cell adhesion and Wnt signaling, we focused our research in two different areas. In our first project, we explore how cells utilize cell-cell interactions to change shape, move, and assemble polarized tissues during morphogenesis and maintain these during tissue homeostasis, and how cells integrate different tools in the complex actin regulatory toolkit to create diverse actin structure. We explore this in Drosophila, using a highly multidisciplinary approach, and recently expanded to include parallel studies in cultured mammalian cells. Proteins on which we focus play key roles in mammalian development and cancer metastasis. Our current efforts explore two key issues in the field. First, we will determine the mechanisms by which cells link cell-cell junction to the actomyosin cytoskeleton to allow cell shape change without disrupting epithelial integrity. We hypothesize that cells use different linkers and junctional architectures to drive different key cell shape change or migratory events. Second, we will build on the existing knowledge of the biochemical functions of individual actin regulators to define how cells integrate these to create the diverse actin structures required during normal development, and how upstream signaling pathways shape this integration. In our second project, we explore how cells choose and maintain fate, using Wnt signaling as a model. Wnt signaling shapes virtually every organ system, plays a key role in homeostasis in many tissues, and is inappropriately activated in several common forms of cancer, including colon cancer, the second leading cause of cancer deaths. In the past ten years we focused on the tumor suppressor Adenomatous polyposis coli (APC), a key negative regulator of the Wnt signaling that is mutated in 80% of all colon cancers. APC also plays Wnt- independent roles in regulating the cytoskeleton, thus facilitating high-fidelity chromosome segregation, which is also disrupted in cancer. Our long-term goal is to determine how APC and its protein partners regulate both Wnt signaling and the cytoskeleton during normal development and homeostasis, and how that goes wrong in cancer. In the next funding period we will address two key questions in the field. First, we will define the mechanisms by which the multiprotein destruction complex targets the Wnt effector ß-catenin for phosphorylation, transfers it to an E3 ligase for ultimate proteasomal destruction, and how Wnt signals regulate its activity. This is a paradigm for how regulated protein stability regulates cell signaling. Second, we will explore the regulation of genome stability, defining how APC acts as a cytoskeletal regulator to ensure mitotic fidelity, and defining mechanisms that buffer its loss. More broadly, we will determine how the genetic circuitry of mitotic regulation and checkpoints is re-drawn in different tissues to meet different needs, contrasting epithelial cells and neural progenitors, using our newly developed Drosophila model of microcephaly.