Intercellular Communication in the Eye Lens

描述(申请人提供)：连接蛋白形成缝隙连接细胞间通讯(GJIC)对于晶状体的代谢稳态是必不可少的。除了缝隙连接外，连接蛋白还形成半通道，允许分子在细胞内交换。然而，对晶状体中半通道的功能和调节知之甚少。此外，晶状体连接蛋白还受到翻译后修饰、分化晶状体纤维时的磷酸化以及成熟晶状体纤维中蛋白水解性截断的影响。我们的长期目标是了解连接蛋白分子在晶状体内稳和透明中的分子机制(S)和功能意义。其目的是阐明缝隙连接和半通道的独特机制，以及在正常和氧化应激条件下连接蛋白50的翻译后修饰的作用。中心假设是：(1)GJIC和半通道在晶状体中发挥独特的作用；(2)在分化纤维过程中，由于PKA对CX50的磷酸化，GJIC和/或半通道功能增加，而由于CX50截断成熟纤维，对缝隙连接/半通道的适应性调节增强了晶状体对氧化损伤的抵抗力。将追求三个具体目标：1)确定缝隙连接和半通道在区分晶状体纤维中的独特作用。2)确定晶状体中CX50的PKA磷酸化的功能重要性。3)确定发育相关的CX50截断在成熟晶状体纤维中的机制作用。本研究的创新之处之一在于，本研究旨在剖析缝隙连接和半通道的独特作用，以及翻译后修饰在晶状体纤维分化和成熟过程中的作用。此外，我们将使用我们新开发的体外方法来剖析CX50及其截断在晶状体皮质和中心核心中的作用。我们期望，阐明晶状体连接蛋白调控的分子机制(S)及其形成的通道，将有助于我们更好地了解晶状体在正常和病理条件下的一般稳态过程。我们的研究结果将具有重要意义，因为新发现的知识将为治疗晶状体疾病的新策略做出新的有益贡献，例如年龄相关性白内障，并为药物的发现和开发铺平道路。

DESCRIPTION (provided by applicant): Connexin-forming gap junction intercellular communication (GJIC) is essential for the metabolic homeostasis of the lens. In addition to gap junctions, connexins forms hemichannels, permitting exchange of molecules across the cell. However, little is known regarding the function and regulation of hemichannels in the lens. In addition, lens connexin is subjected to posttranslational modifications; phosphorylation in differentiating lens fibers and proteolytic truncation in mature lens fibers. Our long-range goal i to understand the molecular mechanism(s) and functional significance of connexin molecules in lens homeostasis and transparency. The objective is to elucidate the distinctive, mechanistic roles of gap junctions and hemichannels, and role of posttranslational modifications of connexin (Cx) 50 under normal and oxidative stress conditions. The central hypotheses are: (1) GJIC and hemichannels play distinctive roles in the lens; (2) Increased GJIC and/or hemichannel function due to Cx50 phosphorylation by PKA in differentiating fibers and adaptive-regulation of gap junctions/hemichannels due to Cx50 truncation in mature fibers enhance lens resistance to oxidative damages. Three specific aims will be pursued: 1) Determine the distinctive roles of gap junctions and hemichannels in the differentiating lens fibers. 2) Determine the functional importance of PKA phosphorylation of Cx50 in the lens. 3) Determine the mechanistic role of developmentally associated truncation of Cx50 in mature lens fibers. One of the innovative aspects is that this proposal aims to dissect distinctive roles of gap junctions and hemichannels, and posttranslational modifications in differentiating and mature lens fibers. Moreover, we will use our newly developed ex vivo approach to dissect the roles of Cx50 and its truncation in cortex and center core of the lens. It is our expectation that elucidation of the molecular mechanism(s) involved in the regulation of lens connexins and the channels formed by them will provide a better understanding of the general homeostatic process of lens under normal and pathological conditions. The outcomes of our research will be significant because the newly discovered knowledge should make novel and beneficial contributions to new strategies for the treatment of lens disorders, e.g. age-related cataracts, and pave way for drug discovery and development.