CELL ADHESION AND REGULATION OF CARDIAC MYOCYTE FUNCTION

钙粘蛋白在胚胎发育过程中起关键作用。 在细胞外，它们介导特异性细胞-细胞粘附， 在细胞内，它们与连环蛋白相互作用，并通过它们与 肌动蛋白细胞骨架 越来越多的证据表明， 通过钙粘蛋白和连环蛋白诱导多种细胞反应。 在 心肌，N-钙粘蛋白已被证明是重要的维持 结构和功能，包括肌原纤维组织和肌细胞 收缩。 这个项目的目标是建立一个角色，N- 钙粘蛋白在心肌形成的早期事件。 我们的初步结果 表明需要N-钙粘蛋白来维持之间的粘附 小鼠早期胚胎的心肌细胞。 我们认为N-钙粘蛋白- 介导的细胞粘附调节细胞间通讯和肌原纤维 在早期心肌中形成。 我们将分析心肌细胞从N-钙粘蛋白缺陷的能力， 转基因小鼠胚胎组装间隙连接和桥粒。 的 表达和细胞定位 收缩蛋白也将在N-cadherin-minus心脏中进行检查。 肌细胞 N-钙粘蛋白双敲除（DKO）胚胎干（ES）细胞系 将建立。 在用加塔-4转染后， ES细胞在体外可分化为心肌细胞。 的能力 上皮（E-）钙粘蛋白，以挽救N-钙粘蛋白缺乏 将确定心肌细胞。 DKO ES细胞系将是 用突变的N-钙粘蛋白转染，以确定哪些结构域 在心肌细胞中发挥正常功能所必需的。 突变型N-钙粘蛋白 包括功能改变、嵌合和截短分子。 最后， 我们将确定N-钙粘蛋白的上调是否与正常的 心脏发育 这项研究将阐明N-钙粘蛋白在心肌中的作用， 阵 从更广泛的角度来看，我们的成果将有助于我们 了解钙粘蛋白如何调节细胞形态和行为。 他们还将阐明钙粘蛋白在肿瘤细胞中功能的特异性。 特别是组织，这里是心肌

Cadherins play critical roles during embryonic development. Extracellularly, they mediate specific cell-cell adhesion, while intracellularly they interact with the catenins and through them with actin cytoskeleton. There is growing evidence that signal transduction via cadherins and catenins induces a variety of cellular responses. In cardiac muscle, N-cadherin has been shown to be important for maintaining structure and function, including myofibril organization and myocyte contraction. The goal of this project is to establish a role for N- cadherin in early events of cardiac muscle formation. Our initial results indicate that N-cadherin is required for maintaining the adhesion between cardiac myocytes of the early mouse embryo. We propose that N-cadherin- mediated cell adhesion regulates intercellular communication and myofibril formation in the early myocardium. We will analyze the ability of cardiac myocytes from N-cadherin-deficient transgenic mouse embryos to assemble gap junctions and desmosomes. The expression and cellular localization of contractile proteins will also be examined in N-cadherin-minus cardiac myocytes. N-cadherin double knockout (DKO) embryonic stem (ES) cell lines will be established. After transfection with GATA-4, the N-cadherin-null ES cells will be differentiated into cardiac muscle in vitro. The ability of epithelial (E-) cadherin to rescue the N-cadherin-deficient cardiomyocytes will be determined. The DKO ES cell line will be transfected with mutant N-cadherins to determine which domains are required for its proper function in cardiac myocytes. Mutant N-cadherins include functionally altered, chimeric, and truncated molecules. Lastly, we will determine if upregulation of N-cadherin is compatible with normal cardiac development. The proposed research will elucidate N-cadherin's role in myocardium formation. In broader terms our results will contribute to our understanding of how cadherins regulate cell morphology and behavior. They also will shed light on the specificity of cadherin function in a particular tissue, in this case cardiac muscle.