Catenins, cadherins and their interactions

连环蛋白、钙粘蛋白及其相互作用

• 批准号: 8000022
• 负责人: William I Weis
• 金额: $ 8.25万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-01-07 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8000022
• 关键词: Actins; Adherens Junction; Adult; Affinity; Basic Science; Binding; Biochemical; Bulla; C-terminal; Cadherins; Calorimetry; Cell Adhesion; Cell Adhesion Molecules; Cell Fate Control; Cell membrane; Cells; Complex; Congenital Heart Defects; Crystallography; Cytoplasmic Tail; Cytoskeleton; Data; Defect; Desmosomes; Development; Dictyostelium; Dictyostelium discoideum; Disease; E-Cadherin; EP300 gene; Epithelial; Epithelium; Family; Gene Targeting; Genes; Goals; Homologous Gene; Intercellular Junctions; Intermediate Filaments; Length; Link; Malignant Neoplasms; Mechanics; Methods; Molecular; Mutation; N-Cadherin; N-terminal; Neoplasm Metastasis; Nephroblastoma; Neurons; Nuclear; Orycteropodidae; Pathway interactions; Peptides; Phosphorylation; Physarum polycephalum; Process; Property; Proteins; Reporting; Research Project Grants; Role; Signal Pathway; Signal Transduction; Skin; Solid; Structure; Synapses; Tail; Tissues; Titrations; Transcription Coactivator; Transcription Repressor/Corepressor; Ubiquitination; Vinculin; X-Ray Crystallography; actin 2; base; cancer cell; cell assembly; desmoplakin; gene repression; molecular assembly/self assembly; plakoglobin; public health relevance; receptor; reconstitution; synaptogenesis; three dimensional structure; transcription factor

DESCRIPTION (provided by applicant): The assembly of cells into tissues depends upon formation of intercellular junctions. In adherens junctions, the catenins link transmembrane cadherin cell adhesion molecules to the actin-based cytoskeleton, and in desmosomes an analogous protein assembly links cadherins to intermediate filaments. Adherens junction assembly is an essential step in the development of cell and tissue structure, and loss of these junctions is a hallmark of metastasizing cancer cells. Likewise, cell-cell contacts liked to intermediate filaments are essential for the mechanical strength and integrity of tissues such as the skin and heart, and defects in these assemblies are responsible for a number of severe skin blistering diseases. The adherens junction protein 2-catenin also serves as a transcriptional coactivator in the Wnt signaling pathway that controls cell fate determination and in the normal renewal of tissues in the adult. In many cancers, stabilization of 2-catenin due to mutations in Wnt pathway components results in inappropriate activation of Wnt target genes. The goal of this proposal is to achieve a mechanistic understanding of cell adhesion assemblies and of 2- catenin in Wnt signaling by using purified components to reconstitute key parts of these molecular complexes. Biochemical and biophysical methods will be used to determine the structures and affinities of these interactions. 1. The assembly and structure of actin-based cell-cell contacts will be investigated in epithelia and neurons by examining the similarities and differences between the epithelial and neuronal versions of 1-catenin, in particular its 2-catenin and actin-binding properties. We will also study the interactions of EPLIN with 1-E- catenin and actin to assess its potential role in linking the cadherin-catenin complex to actin. 2. The evolutionary origins of cell adhesion assemblies will be studied by examining homologs of 1- and 2- catenin in the slime mold Dictyostelium discoideum. 3. Structures of desmosomal cadherins bound to plakoglobin will be determined, as will the N- and C-terminal portions of desmoplakin, which links the cadherin-plakoglobin complex to intermediate filaments. 4. The mechanisms by which phosphorylation and ubiquitination required for 2-catenin destruction are controlled by Wnt signaling will be studied, in particular how phosphorylation of the Wnt receptor Lrp6 inhibits phosphorylation of 2-catenin, and how the phosphorylation complex is linked to the ubiquitination machinery. 5. The molecular mechanism of how Tcf/Lef-family transcription factors control Wnt target signaling will be investigated by determining structures of Lef-1 bound to a transcriptional repressor and to a 2-catenin-activator complex. PUBLIC HEALTH RELEVANCE: During development, cells differentiate and form specific contacts with other cells in order to create tissues. Defects in this process give rise to developmental abnormalities, and loss of cell-cell contacts occurs in cancer metastasis, when cancer cells escape from a solid tissue, and in other diseases. This basic research project seeks to understand the molecular assemblies responsible for these processes.

描述（由申请人提供）：细胞组装到组织中取决于形成细胞间连接。在粘附连接中，catenins将跨膜钙粘着蛋白细胞粘附分子与基于肌动蛋白的细胞骨架联系起来，在脱糖体中，类似的蛋白质组装将钙粘着蛋白连接到中间细丝。粘附连接组件是细胞和组织结构发展的重要步骤，这些连接的丧失是转移癌细胞的标志。同样，喜欢中间细丝的细胞 - 细胞接触对于皮肤和心脏等组织的机械强度和完整性至关重要，并且这些组装中的缺陷导致许多严重的皮肤膨胀疾病。粘附连接蛋白2-catenin还用作控制细胞命运确定和成年组织正常续订的Wnt信号传导途径中的转录共激活因子。在许多癌症中，由于Wnt途径成分中的突变导致2-catenin的稳定导致Wnt靶基因的不适当激活。该提案的目的是通过使用纯化的组件来重建这些分子复合物的关键部分来实现对细胞粘附组件和2-链氨酸蛋白的机械理解。生化和生物物理方法将用于确定这些相互作用的结构和亲和力。 1。将通过检查1-catenin的上皮和神经元版之间的相似性和差异，尤其是其2-catenin和肌动蛋白结合特性，从而在上皮和神经元中研究基于肌动蛋白的细胞接触的组装和结构。我们还将研究eplin与1-E- catenin和肌动蛋白的相互作用，以评估其在将钙粘蛋白 - 钙蛋白复合物与肌动蛋白联系起来的潜在作用。 2。将研究细胞粘附组件的进化起源，通过检查粘液模具dictyostelium discoideum中的1-和2-蛋白酶的同源物来研究。 3。将确定与plakoglobin结合的脱乳小蛋白的结构，将cadherin-plakoglobin络合物与中间细丝联系起来的脱氨木蛋白的N-和C末端部分也是如此。 4。将研究2-catenin销毁所需的磷酸化和泛素化的机制，特别是研究Wnt信号传导，特别是Wnt受体LRP6的磷酸化如何抑制2-catenin的磷酸化，以及如何将磷酸化复合物与Ubiquitination Marchinery Marchinery链接到Ubiquitination Machinery。 5。将通过确定与转录阻遏物和2-catenin-激活剂复合物结合的LEF-1结构来研究WNT目标信号传导的分子机制。公共卫生相关性：在开发过程中，细胞与其他细胞区分并形成特定的接触以创建组织。在此过程中的缺陷导致发育异常，当癌细胞从固体组织中逸出以及其他疾病中时，癌细胞转移中会发生细胞 - 细胞接触的丧失。这个基础研究项目旨在了解负责这些过程的分子组件。