Regulation of epithelial contact inhibition by Rac effector proteins

Rac 效应蛋白对上皮接触抑制的调节

基本信息

批准号：
7254943
负责人：
Mirjam M. Zegers
金额：
$ 26.07万
依托单位：
UNIVERSITY OF CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-07-01 至 2011-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7254943
关键词：
Adaptor Signaling Protein Address Adherens Junction Adhesions Affect Behavior Binding Biological Models Biology Cancer Center Cell Adhesion Molecules Cell Density Cell Line Cell Proliferation Cell membrane Cell physiology Cells Complex Contact Inhibition Data Defect Development Diagnostic Disease Drug Design E-Cadherin Environment Epithelial Epithelial Cells Event Focal Adhesions GIT1 gene Goals Growth Factor Guanine Guanine Nucleotide Exchange Factors Homeostasis Hyperplasia In Vitro Kinetics Lateral Lipids Localized MDCK cell MEKs Mediating Membrane Mesenchymal Microscopy Molecular Morphogenesis Morphology Organism Outcome Pathway interactions Phenotype Phosphatidylinositols Phosphotransferases Play Process Production Proteins Purpose RNA Interference Recruitment Activity Regulation Reporting Research Research Personnel Role Signal Pathway Signal Transduction Site Testing Thinking Tissues base carcinogenesis cell growth cell motility extracellular human GIT1 protein inhibitor/antagonist injury and repair innovation insight kidney epithelial cell member mutant novel p21-activated kinase 1 paxillin phosphatidylinositol 3-phosphate phosphoinositide 3-phosphate programs research study rho rho GTP-Binding Proteins small molecule

项目摘要

DESCRIPTION (provided by applicant): Contact inhibition is the ability of cells to inhibit motility and proliferation after forming cell-cell contacts. Our long-term goal is to understand the molecular mechanism underlying contact inhibition in normal epithelial cells. Epithelial cell-cell contacts are mainly formed by E-cadherin-based adherens junctions, which function as a focal point of many signaling pathways regulating various cellular behaviors, including most likely, contact inhibition. We recently reported that translocation of a protein complex to cell-cell contacts is pivotal to the establishment of contact inhibition. These complexes, defined here as "Pak:PIX complexes", minimally contain the Rac/cdc42 effector molecules p21-activated kinase 1 (Pak1) and the Rac/cdc42-guanine exchange factor betaPIX. In subconfluent cells, Pak:PIX complexes are in focal contacts, where they regulate cell motility and morphology. How they are recruited to cell-cell contact sites and how this translocation can regulate proliferation, is however unknown. The objective of this proposal is to characterize the mechanisms by which Pak:PIX complexes translocate from focal contacts to cell-cell contacts when cells become confluent, and to determine how this affects mitogenic signaling through the MEK-ERK pathway. The central hypothesis is that, upon E-cadherin-mediated activation of phosphatidyl inositol-3-kinase, Pak:PIX complexes are recruited to cell-cell contacts. This translocation may uncouple mitogenic signaling. In aim 1, we will characterize the translocation of Pak:PIX complexes and will identify new binding partners, in aim 2, we will further define the role of E-cadherin, and in aim 3, we will investigate how Pak:PIX complexes control contact inhibition by regulating the mitogenic MEK-ERK signaling pathway. The proposed research is important, as it will help to understand how localized, subcellular dynamic regulation of Rho effector proteins integrates the many signals that cells receive from their extracellular environment. The experiments outlined in this proposal will specifically address the mechanism that regulates the cell density-dependent localization of Pak:PIX complexes, which is crucial for contact inhibition. Identification of the mechanism underlying contact inhibition will allow us to identify specific target molecules that can be employed for diagnostic purposes or drug design. We anticipate that the results of our studies will yield novel and fundamental insights into the biology of epithelial morphogenesis.

描述（由申请人提供）：接触抑制是细胞在形成细胞细胞接触后抑制运动性和增殖的能力。我们的长期目标是了解正常上皮细胞中接触抑制的分子机制。上皮细胞 - 细胞接触主要由基于E-钙粘蛋白的粘附连接形成，该连接是许多信号通路的焦点，这些信号通路调节各种细胞行为，包括最有可能的接触抑制。我们最近报道说，将蛋白质复合物转移到细胞 - 细胞接触对建立接触抑制至关重要。这些复合物在这里定义为“ PAK：PIX复合物”，最少包含RAC/CDC42效应分子P21激活的激酶1（PAK1）和RAC/CDC42-鸟嘌呤交换因子Betapix。在亚汇合细胞中，PAK：PIX复合物处于局灶性接触中，它们调节细胞运动和形态。但是，它们是如何招募到细胞 - 细胞接触位点的，但是这种易位如何调节增殖。该建议的目的是表征PAK：PIX复合物在细胞汇合时从焦点接触到细胞细胞接触的机制，并确定这如何通过MEK-ERK途径影响有丝分裂信号传导。中心假设是，在E-钙粘蛋白介导的磷脂酰肌醇-3-激酶的激活后，PAK：PIX复合物被募集到细胞细胞接触中。这种易位可能会脱离有丝分裂信号。在AIM 1中，我们将表征PAK：PIX复合物的易位，并将识别新的结合伴侣，在AIM 2中，我们将进一步定义E-钙粘蛋白的作用，在AIM 3中，我们将研究PAK：PIX Complecter如何通过调节有丝分裂的MEK-ERK-ERK信号通路来调节pak：Pix Complecter如何控制接触抑制。拟议的研究很重要，因为它将有助于了解Rho效应蛋白的局部亚细胞动态调节如何整合细胞从其细胞外环境中获得的许多信号。该提案中概述的实验将特别解决调节PAK细胞密度依赖性定位的机制：PIX复合物，这对于接触抑制至关重要。鉴定接触抑制的机制将使我们能够识别可用于诊断目的或药物设计的特定靶标分子。我们预计我们的研究结果将产生对上皮形态发生生物学的新颖和基本见解。