Regulation of transport mechanisms in lens cells

描述(申请人提供)：晶状体细胞利用Na，K-ATPase 保持稳定的细胞质成分，从而保持透明度。为了 克服如此大的质量和紧密的离子调节的困难 填充细胞，晶状体是专门的，以至于上皮细胞，特别是 在晶状体赤道，保持较高的Na，K-ATPase活性，而纤维细胞 Na，K-ATPase活性低。Na，K-ATPase的这种不均匀分布 活动很重要，因为它提供了循环的动力 在后极向外流动，在前极向内流动的离子流 杆子。然而，我们对不平等的空间是如何 Na，K-ATPase活性的定位是因为所有的晶状体细胞， 上皮和纤维中，都有类似丰富的Na，K-ATPase蛋白。这个 晶状体细胞Na，K-ATPase蛋白表达水平与Na不一致， K-ATPase活性。其他因素似乎也牵涉其中。在这里，我们计划研究如何 上皮细胞达到并维持较高的Na，K-ATPase活性。研究 将进行研究，以研究Na，K-ATPase活性与 晶状体上皮细胞合成新的Na，K-ATPase蛋白的能力 I)；确定Na，K-ATPase的氧化翻译后修饰 蛋白质有助于降低Na，K-ATPase活性(AIM II)； 确定a亚基的酪氨酸磷酸化是否会导致 Na，K-ATPase活性变化(Aim III)。这些研究的结果将 让我们更好地了解晶状体离子调节和晶状体细胞 支持长期保持镜头透明度的专业化认证。

DESCRIPTION (provided by applicant): Lens cells utilize Na, K-ATPase to preserve stable cytoplasmic composition and thus transparency. In order to overcome the difficulty of ion regulation in such a large mass of tightly packed cells, the lens is specialized such that epithelial cells, particularly at the lens equator, maintain a high activity of Na, K-ATPase while fiber cells have low Na, K-ATPase activity. This unequal distribution of Na, K-ATPase activity is important because it provides the driving force for circulating ionic currents that flow outward at the posterior pole, inward at the anterior pole. However there is a gap in our knowledge of how the unequal spatial localization of Na, K-ATPase activity is established because all lens cells, epithelium and fibers, have a similar abundance of Na, K-ATPase protein. The level of Na, K-ATPase protein expression in lens cells does not tally with Na, K-ATPase activity. Other factors seem to be involved. Here we plan to study how the epithelial cells achieve and maintain high Na, K-ATPase activity. Studies will be conducted to examine the link between activity of Na, K-ATPase and the ability of lens epithelial cells to synthesize new Na, K-ATPase protein (Aim I); determine whether oxidative posttranslational modification of Na, K-ATPase protein contributes to reduction of Na, K-ATPase activity (Aim II); and to determine whether tyrosine phosphorylation of the a subunit can bring about changes in Na, K-ATPase activity (Aim III). Results from these studies will give us a better understanding of lens ion regulation and lens cell specializations that underpin long term maintenance of lens transparency.