Tyrosine Phosphorylation in Lens Cell Differentiation

晶状体细胞分化中的酪氨酸磷酸化

• 批准号: 6754439
• 负责人: A. Sue Menko
• 金额: $ 35.33万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-02 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6754439
• 关键词: biological signal transduction; cadherins; cataract; cell differentiation; chick embryo; embryo /fetus tissue /cell culture; enzyme activity; enzyme induction /repression; fluorescence microscopy; gel electrophoresis; immunoelectron microscopy; immunoprecipitation; lens; lens disorder; lens proteins; phosphorylation; physiologic stressor; protein structure function; protein tyrosine kinase; thermodynamics; tissue /cell culture; western blottings

DESCRIPTION (provided by applicant): Activation of Src tyrosine kinases occurs in response to oxidative, heat, and UV stress, all stress stimuli that promote the formation of lens cataract. We have found that inhibition of Src family tyrosine kinases (SFKs) blocks the development of lens opacity. In this proposal we will identify the molecular mechanisms by which SFK activation induces cataract formation. Our long term objectives are to identify the alterations in signaling pathways that lead to lens disease. The signaling intermediates in these networks are likely candidates for pharmaceutical intervention to suppress the formation of lens opacities. Key to understanding how the activation of SFKs leads to cataract formation is the delineation of SFK functions in normal lens differentiation and development. We will determine the mechanisms whereby SFKs regulate cadherin function in the developing embryonic lens. To extend these studies to the pathophysiology of lens cataract, we will examine the structural and functional targets of inappropriately activation of SFKs, focusing on cadherin junction destabilization, using two Src-induced lens disease models. One is an in vitro model in which lens cell cultures are transformed with a temperature sensitive v-Src kinase with which we will dissect the molecular affects of Src activation on the stabilization and function of lens cadherin junctions at different stages of development. These studies will be paralleled in a whole lens culture model that closely approximates stress-induced cataract. In this model we will be able to link the molecular changes that result from the inappropriate activation of SFKs with the formation of lens opacities. We hypothesize that one mechanism by which SFKs influence lens cell differentiation is through their regulation of cadherin complexes and that inappropriate regulation of the SFK signaling pathways induces lens cataracts by destabilizing cadherin junctions. We propose to 1) determine the mechanisms whereby Src family kinases regulate cadherin function in normal lens cell differentiation; 2) determine the mechanisms whereby constitutive activation of the Src kinase interferes with the structure and function of lens cadherin junctions, using v-Src transformed lens cell cultures as a model for stress-induced lens disease; and 3) determine the mechanisms whereby the inappropriate activation of Src family kinases, through their targeting of cadherin junctions, induces formation of lens cataracts.

描述（由申请人提供）：SRC酪氨酸激酶的激活是响应氧化，热和紫外应激而发生的，这是所有促进透镜白内障形成的应力刺激。我们发现，抑制SRC家族酪氨酸激酶（SFK）阻碍了透镜不透明度的发展。在此提案中，我们将确定SFK激活诱导白内障形成的分子机制。我们的长期目标是确定导致晶状体疾病的信号传导途径的改变。这些网络中的信号传导中间体可能是药物干预的候选者，以抑制晶状体不透明度的形成。了解SFK的激活如何导致白内障形成的关键是SFK函数在正常晶状体分化和发育中的描述。我们将确定SFK在发育中的胚胎晶状体中调节钙粘着蛋白功能的机制。为了将这些研究扩展到透镜白内障的病理生理，我们将使用两个SRC诱导的晶状体疾病模型研究SFK不适当激活的结构和功能靶标，重点介绍了钙粘蛋白的结局。一个是一种体外模型，其中透镜细胞培养物用温度敏感的V-SRC激酶转化，我们将在不同的发育阶段剖析SRC激活对晶状体钙粘着蛋白连接的稳定和功能的分子影响。这些研究将在整个晶状体培养模型中平行，该模型紧密近似于应激诱导的白内障。在此模型中，我们将能够将不适当激活的分子变化与晶状体不透明的形成联系起来。我们假设SFK会影响透镜细胞分化的一种机制是通过调节钙粘蛋白复合物的调节，而对SFK信号通路的不当调控会通过破坏钙粘着蛋白联结的稳定而引起透镜白内障。我们建议1）确定SRC家族激酶在正常晶状体细胞分化中调节钙粘蛋白功能的机制； 2）确定使用V-SRC转化的透镜细胞培养物作为应激诱导的晶状体疾病的模型，确定SRC激酶的本构激活干扰晶状体钙粘着蛋白连接的结构和功能的机制； 3）确定SRC家族激酶不适当激活的机制，通过靶向钙粘蛋白连接，引起透镜白内障的形成。