Rnd Effector Molecules in Epithelial Cell Transformation

上皮细胞转化中的研究效应分子

• 批准号: 7016342
• 负责人: STEEN HENNING HANSEN
• 金额: $ 37.13万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-03-01 至 2008-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7016342
• 关键词: MDCK cell; cellular polarity; epithelium; fibroblasts; guanine nucleotide binding protein; guanosinetriphosphatase activating protein; inhibitor /antagonist; mitogen activated protein kinase; neoplastic transformation; protein protein interaction; protein structure function; tissue /cell culture

DESCRIPTION (provided by applicant): The small GTPase Ras relays signals from activated cell surface receptors to intracellular signaling pathways. In adenocarcinomas, which originate from polarized epithelial cells, Ras signaling is often deregulated as a result of activating mutations or gene amplification. The mechanisms by which oncogenic Ras elicits transformation of polarized epithelial cells are poorly understood. A major effector pathway of Ras signaling is the Raf-MEK-ERK pathway, which mimics numerous effects of Ras on cells. Expression of activated Ras or Raf in polarized epithelial cells leads to profound alterations in the actin cytoskeleton and associated changes in cellular architecture. The actin eytoskeleton is subject to control by Rho family GTP-binding proteins. Ras or Raf activation in polarized epithelial cells leads to induced expression of the Rho-like protein Rnd3, which appears to function as an endogenous antagonist to Rho proteins. Accordingly, effects of Rnd proteins on cells are counteracted by expression of activated forms of Rho proteins. Virtually nothing is known about effector molecules of Rnd signaling. It is important to identify effectors of Rnd proteins as their expression in cells elicits a phenotype that suggests that they play key roles in cell transformation and developmental processes. In new studies we have identified the Rho GTPase activating protein p190 as a putative effector molecule of Rnd signaling. Aim 1 is to dissect the interaction between Rnd and p190 proteins and to generate an inhibitory molecule of this interaction. Aim 2 is to test the hypothesis that the interaction between Rnd and p190 molecules affects functional domains of the p190 molecule, and that p190 is an effector molecule of Rnd proteins in vivo using cells in which p190 has been knocked out. Aim 3 addresses whether the Rnd-p190 interaction is critical to oncogenic transformation of polarized epithelial by the Ras activated Raf-MEK-ERK pathway using the inhibitory molecule generated in Aim 1. Together, the proposed studies will elucidate mechanisms whereby Ras transforms epithelial cells leading to invasion and metastasis.

描述（由申请人提供）： 小GTPase RAS将信号从活化的细胞表面受体传递到细胞内信号通路。在起源于极化上皮细胞的腺癌中，由于激活突变或基因扩增，RAS信号通常被放松。对极化上皮细胞的致癌Ras引起转化的机制知之甚少。 RAS信号传导的主要效应子途径是RAF-Mek-ERK途径，它模拟了RAS对细胞的众多影响。激活的RAS或RAF在极化上皮细胞中的表达会导致肌动蛋白细胞骨架的深刻改变以及细胞结构的相关变化。肌动蛋白眼骨骨骼受Rho家族GTP结合蛋白的控制。极化上皮细胞中的Ras或RAF激活导致Rho样蛋白RND3的诱导表达，该蛋白RND3似乎是Rho蛋白的内源性拮抗剂。因此，RND蛋白对细胞的作用通过活化形式的Rho蛋白的表达来抵消。实际上，关于RND信号的效应分子，几乎一无所知。重要的是要识别RND蛋白的效应子作为其在细胞中的表达引起的表型，表明它们在细胞转化和发育过程中起关键作用。在新的研究中，我们已经将Rho GTPase激活蛋白p190确定为RND信号的推定效应子分子。目的1是剖析RND和P190蛋白之间的相互作用，并产生这种相互作用的抑制分子。目的2是测试以下假设：RND和P190分子之间的相互作用会影响P190分子的功能结构域，而P190是使用P190在体内rnD蛋白的效应分子，其中P190被淘汰了。 AIM 3解决了使用AIM 1中产生的抑制性分子，RAS激活的RAF-MEK-ERK途径对偏振上皮的致癌转化是否至关重要。拟议的研究将阐明RAS将RAS转化，从而导致上皮细胞导致侵袭和转移。