Cortactin in Cell Motility and Invasion

产品说明：该研究项目的重点是了解F-肌动蛋白结合蛋白Corpine如何在细胞运动和肿瘤细胞侵袭中发挥作用。拟议的研究的长期目标集中在corneumn和相关蛋白在板状伪足功能中的作用，因为它涉及信号转导和运动，以及corneumn过表达如何影响细胞运动，粘附和肿瘤细胞侵袭。本申请具体说明了corneumn在基于Arp 2/3-F-肌动蛋白的皮质细胞骨架的组织中的功能以及corneumn如何用于调节正常和肿瘤细胞的运动。Corpine是多种酪氨酸激酶（包括Src）的底物，在30%的头颈部鳞状细胞癌（HNSCC）中过表达。基于初步的数据，它被假定，皮质蛋白动态调节皮质肌动蛋白细胞骨架的机制，涉及酪氨酸磷酸化沿着激活和保护Arp 2/3-F-肌动蛋白网络。本文所述的研究将使用成纤维细胞和HNSCC细胞系的生物化学和细胞生物学分析来探索以下假设：corneumn在细胞迁移过程中起调节和稳定皮质Arp 2/3-F-肌动蛋白网络的作用，并且corneumn过表达导致Arp 2/3-F-肌动蛋白网络的动态调节增强导致HNSCC侵袭增加。在目标1中，我们将解决如果corneumn酪氨酸磷酸化影响Arp 2/3肌动蛋白成核活性及其与Arp 2/3-F-actin网络的关联，如果corneumn酪氨酸磷酸化影响板状伪足动力学，并确定corneumn是否保护Arp 2/3-F-actin网络不被ADF/cofilin蛋白分解。目的2将检测通过RNAi减少或消除coronin表达的细胞，以确定coronin如何影响皮质肌动蛋白细胞骨架，细胞迁移和粘附。目的3将通过确定Arp 2/3复合物结合和激活是否在过表达corneumn的HNSCC细胞系中增强来检查corneumn过表达如何影响HNSCC的侵袭特性，并确定HNSCC中corneumn过表达是否导致细胞侵袭和细胞外基质蛋白水解增加。完成所提出的目标将提供更好地了解corneumn如何在细胞迁移和肿瘤细胞侵袭/转移中发挥作用。

DESCRIPTION: The focus of this research project is to understand how cortactin, an F-actin-binding protein, functions in cell motility and tumor cell invasion. The long-term goal of the proposed research centers on the role of cortactin and associated proteins in lamellipodia function as it pertains to signal transduction and motility, and how cortactin overexpression influences cell motility, adhesion and tumor cell invasiveness. This application specifically addresses the function of cortactin in the organization of the Arp2/3-F-actin based cortical cytoskeleton and how cortactin serves to regulate normal and tumor cell movement. Cortactin is a substrate for multiple tyrosine kinases, including Src, and is over expressed in 30% of head and neck squamous cell carcinomas (HNSCCs). Based on preliminary data, it is posited that cortactin dynamically regulates the cortical actin cytoskeleton by a mechanism that involves tyrosine phosphorylation along with activation and protection of Arp2/3-F-actin networks. The studies described here will use biochemical and cell biological analysis of fibroblast and HNSCC cell lines to explore the hypothesis that cortactin functions to regulate and stabilize cortical Arp2/3-F-actin networks during cell migration, and that enhanced dynamic regulation of Arp2/3-F-actin networks resultant from cortactin overexpression leads to increased invasion of HNSCC. In Aim 1, we will address if cortactin tyrosine phosphorylation affects Arp2/3 actin nucleation activity and its association with Arp2/3-F-actin networks, if cortactin tyrosine phosphorylation influences lamellipodia dynamics, and determine if cortactin protects Arp2/3-F-actin networks from disassembly by ADF/cofilin proteins. Aim 2 will examine cells with reduced or eliminated cortactin expression derived by RNAi to determine how cortactin impacts the cortical actin cytoskeleton, cell migration and adhesion. Aim 3 will examine how cortactin overexpression affects the invasive properties of HNSCC by determining if Arp2/3 complex association and activation are enhanced in HNSCC cell lines overexpressing cortactin, and to determine if cell invasion and extracellular matrix proteolysis is increased as a result of cortactin overexpression in HNSCC. Completion of the proposed Aims will provide a better understanding of how cortactin functions in cell migration and tumor cell invasion/metastasis.