Adhesion dynamics in Drosophila border cell migration

果蝇边缘细胞迁移的粘附动力学

• 批准号: 7010356
• 负责人: Denise J. Montell
• 金额: $ 31.49万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7010356
• 关键词: Drosophilidae; actins; biological signal transduction; cadherins; cell adhesion; cell migration; gene expression; genetic models; guanine nucleotide binding protein; guanosinetriphosphatase activating protein; protein structure function

DESCRIPTION (provided by applicant): Cell migration is a fascinating feature of embryonic development, and improperly regulated cell migration contributes to birth defects and tumor metastasis. We have developed a simple model system for a forward genetic approach to the study of cell motility in vivo, the migration of a subset of follicle cells, known as border cells, in the Drosophila ovary. We have established that multiple extracellular signals regulate their movement. 1) a global steroid hormone signal, ecdysone, acting through the ecdysone receptor and a transcriptional coactivator called Taiman; 2) a highly localized cytokine signal, which activates the JAK/STAT pathway; and 3) several growth factors, which signal through the EGFR and PVR receptor tyrosine kinases to guide the cells to their destination. In addition we have studied a variety of cytoskeleton-associated proteins and cell adhesion molecules that function in border cell migration. This proposal explores the mechanisms by which cell adhesion is dynamically regulated in migrating border cells, an important aspect of cell motility that is not well understood for any cell type. We propose three specific aims. The first is to investigate the mechanisms that govern trafficking and stability of E-cadherin, a homophilic cell-cell adhesion molecule that is required in border cells and in the cells upon which they migrate. To test whether E-cadherin is turned over more rapidly in border cells than in non-migrating follicle cells, we will employ a previously characterized variant of the red fluorescent protein that changes color over time, fused to E-cadherin. We will investigate whether EGFR and PVR signaling destabilizes cell adhesion by phosphorylation of specific tyrosine residues on beta-catenin/Armadillo. We will also determine whether endocytosis is important for regulating cell surface E-cadherin in migrating border cells. We will test whether Drosophila moesin contributes to E-cadherin dynamics. And we will investigate the mechanisms by which Myosin VI contributes to E-cadherin dynamics in border cells. In the second specific aim we propose to investigate in detail the mechanisms by which RhoGAP93B contributes to border cell migration by studying its biochemical activity, its expression pattern, subcellular localization, lethal phenotype and its regulation. Finally we propose to study a putative downstream target of Rho in border cells, rhophilin by characterizing the mutant phenotype, epistasis analysis with Rho and by identifying and characterizing interacting proteins.

描述（由申请人提供）：细胞迁移是胚胎发育的一个令人着迷的特征，细胞迁移调节不当会导致出生缺陷和肿瘤转移。我们开发了一个简单的模型系统，用于研究体内细胞运动的正向遗传方法，即果蝇卵巢中卵泡细胞子集（称为边界细胞）的迁移。我们已经确定多种细胞外信号调节它们的运动。 1) 全局类固醇激素信号，蜕皮激素，通过蜕皮激素受体和称为 Taiman 的转录共激活因子发挥作用； 2）高度局部化的细胞因子信号，激活JAK/STAT通路； 3) 几种生长因子，通过 EGFR 和 PVR 受体酪氨酸激酶发出信号，引导细胞到达目的地。此外，我们还研究了多种在边界细胞迁移中发挥作用的细胞骨架相关蛋白和细胞粘附分子。该提案探讨了迁移边界细胞中细胞粘附动态调节的机制，这是细胞运动的一个重要方面，但对于任何细胞类型来说尚不清楚。我们提出三个具体目标。第一个是研究控制 E-钙粘蛋白的运输和稳定性的机制，E-钙粘蛋白是一种同质细胞间粘附分子，是边界细胞及其迁移的细胞所必需的。为了测试 E-钙粘蛋白在边缘细胞中是否比非迁移滤泡细胞中的更新速度更快，我们将使用先前表征的红色荧光蛋白变体，该变体会随着时间的推移而改变颜色，并与 E-钙粘蛋白融合。我们将研究 EGFR 和 PVR 信号传导是否通过 β-连环蛋白/犰狳上特定酪氨酸残基的磷酸化来破坏细胞粘附的稳定性。我们还将确定内吞作用对于调节迁移边界细胞中的细胞表面 E-钙粘蛋白是否重要。我们将测试果蝇模蛋白是否有助于 E-钙粘蛋白动力学。我们将研究肌球蛋白 VI 对边缘细胞中 E-钙粘蛋白动态的影响机制。在第二个具体目标中，我们建议通过研究 RhoGAP93B 的生化活性、表达模式、亚细胞定位、致死表型及其调控来详细研究 RhoGAP93B 促进边界细胞迁移的机制。最后，我们建议通过表征突变表型、Rho 上位性分析以及识别和表征相互作用蛋白来研究 Rho 在边缘细胞中的假定下游靶标 rhophilin。