Intercellular Communication in the Eye Lens

描述（由申请方提供）：连接蛋白形成间隙连接细胞间通讯（GJIC）对于透镜的代谢稳态至关重要。除了间隙连接，连接蛋白形成半通道，允许分子在细胞内交换。然而，关于半通道在透镜中的功能和调节知之甚少。此外，透镜连接蛋白经历翻译后修饰;分化中的透镜纤维中的磷酸化和成熟透镜纤维中的蛋白水解截短。我们的长期目标是了解连接蛋白分子在透镜稳态和透明度中的分子机制和功能意义。目的是阐明不同的，机械作用的间隙连接和半通道，和翻译后修饰的连接蛋白（Cx）50在正常和氧化应激条件下的作用。核心假设是：（1）GJIC和半通道在透镜中发挥独特的作用;（2）由于PKA在分化纤维中的Cx 50磷酸化而增加的GJIC和/或半通道功能以及由于成熟纤维中Cx 50截短而引起的间隙连接/半通道的适应性调节增强了透镜对氧化损伤的抵抗力。本研究的目的有三：1）明确缝隙连接和半通道在分化透镜纤维中的独特作用。2)确定透镜中Cx 50的PKA磷酸化的功能重要性。3)确定成熟透镜纤维中发育相关的Cx 50截短的机制作用。其中一个创新的方面是，这个建议的目的是解剖的缝隙连接和半通道，和翻译后修饰的分化和成熟的透镜纤维的独特作用。此外，我们将使用我们新开发的离体方法来剖析Cx 50及其截断在透镜皮质和中心核心中的作用。我们期望阐明参与调节透镜连接蛋白及其形成的通道的分子机制，将更好地理解正常和病理条件下透镜的一般稳态过程。我们的研究成果将是重要的，因为新发现的知识将为治疗透镜疾病（如年龄相关性白内障）的新策略做出新的有益贡献，并为药物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.