Molecular Mechanisms of Cell Migration

细胞迁移的分子机制 项目概要： 细胞外基质（ECM）信号的识别对于许多发育和稳态过程至关重要， 而对信号的误解是诸如转移等疾病的基础。细胞探针ECM线索通过延伸 基于肌动蛋白的突起结合ECM并形成锚以帮助它们向前移动。然而， 关于决定过程和信号通路，将突起的ECM探测转换为定向的 细胞迁移许多传统的显微镜研究假设突起均匀地覆盖着 随机扩散未结合的ECM受体，其随机结合ECM。我们的新方法- 场单分子超分辨率显微镜，我们发现了一个未结合ECM的集中带 位于突起前部的受体具有受体组织的特征性分子模式， 流动性和功能化。这些模式依赖于细胞的增殖活性和特异性受体 细胞质结合域，表明细胞质相互作用，可见仅在单分子水平 调节未结合的整合素如何组织以准备探测ECM。在本提案中，我们将 定义细胞决策过程，将ECM探测转换为定向细胞迁移， ECM受体群体的组织、相互作用和功能化的分子测量， 粘附组装、肌动蛋白调节途径和粘附活性的细胞测量。我们将：1） 定义产生未结合ECM受体组织的全局时空模式的机制， 流动性和构象在细胞突起的前面，调节突起的功能化， 探针ECM; 2）识别结合ECM受体的信号通路，用于分离转化的决定 从决定继续通过肌动蛋白细胞骨架探测ECM到定向迁移的ECM线索 动力学这些研究将直接有助于我们了解细胞识别ECM线索，在许多 发展和稳态过程，以及我们对线索误解的理解， 是疾病如转移的基础。

Molecular Mechanisms of Cell Migration Project summary: Recognition of extracellular matrix (ECM) cues is critical to many developmental and homeostatic processes, and misinterpretation of cues underlies diseases such as metastasis. Cells probe for ECM cues by extending actin-based protrusions to bind ECM and form anchors to help them move forward. However, little is known about the decision processes and signaling pathways that convert ECM probing by protrusions into directed cell migration. Many conventional microscopy studies posit that protrusions are uniformly covered with randomly diffusing unbound ECM receptors that stochastically bind ECM. With our new approach of dense- field single molecule super-resolution microscopy, we have discovered a concentrated band of unbound ECM receptors at the front of protrusions that have characteristic molecular patterns of receptor organization, mobility, and functionalization. These patterns depend on both cellular protrusive activity and specific receptor cytoplasmic binding domains, indicating that cytoplasmic interactions, visible only at the single molecule level regulate how unbound integrins are organized in preparation for probing for ECM. In this proposal we will define the cellular decision processes that convert ECM probing into directed cell migration by integrating molecular measures of the organization, interaction, and functionalization of populations of ECM receptors with cellular measures of the assembly of adhesions, actin regulatory pathways, and protrusive activity. We will: 1) Define mechanisms that create the global spatial-temporal patterns of unbound ECM receptor organization, mobility, and conformation at the front of cell protrusions that regulate the functionalization of protrusions to probe ECM; 2) Identify signaling pathways that bound ECM receptors use to separate the decision to convert an ECM cue into directed migration from the decision to continue to probe the ECM through actin cytoskeletal dynamics. These studies will directly contribute to our understanding of cell recognition of ECM cues in many development and homeostasis processes, as well as our understanding of the misinterpretation of cues, which underlies diseases such as metastasis.