THE ROLE OF LENS MIP IN AGING AND CATARACTOGENESIS

描述(申请人提供)：人体晶状体起紫外线滤光器的作用 将光线聚焦到视网膜上。透明度和高折射率是关键 使晶状体能够正常工作的生物物理特性。为了 保持透明度，纤维细胞必须保持紧密堆积和蛋白质 溶解度。鉴于缺乏对晶状体的血液供应，水的运输， 离子和中性溶质是维护镜片的关键过程 动态平衡。此外，由于镜片的周转或维修很少， 蛋白质，蛋白质结构的变化，包括运输蛋白， 随着年龄的增长而积累。我们的假设是，翻译后的修饰 晶状体水通道，MIP，随着年龄的增长而增加，导致 蛋白质功能与白内障。这项工作的长期目标是 从分子水平认识老年性核性白内障的病因 预防疗法是可以开发出来的。一种方法的设计 只有在以下情况下才能开始阻止这些更改：i)了解 正常纤维细胞成熟过程中的蛋白质结构，II)鉴定 对病变组织特有的晶状体蛋白质的修饰，以及iii) 确定导致功能受损的结构。我们建议 识别和量化特定年龄和特定白内障的晶状体蛋白 并确定这些分子变化是否会导致功能性 改装。 包括临床医生和基础科学家在内的多学科方法是 在这项提案中提出了最先进的质谱学方法 将被用于表征分离的MIP晶状体的结构修改 来自老化和白内障的晶状体。此外，分子生物学方法还有 提出对改性残留物的功能重要性进行测试。具体目标 包括：1)识别分离的MIP晶状体的翻译后修饰 从正常晶状体的解剖切片中，2)识别MIP在 从单个患病晶状体的透明和不透明组织中分离出的膜， 以及3)确定特定修饰在水损害中的作用 渗透性。这项工作的结果有望提供新的详细信息 关于最丰富的积分的结构和函数的信息 晶状体中的膜蛋白，这是基本了解中的关键 正常晶状体成熟和老年性白内障的可能性。

DESCRIPTION (provided by applicant): The human lens acts as a UV filter and to focus light onto the retina. Transparency and high refractive index are key biophysical properties that allow the lens to function properly. In order to maintain transparency, fiber cells must maintain close packing and protein solubility. Given the lack of blood supply to the lens, transport of water, ions, and neutral solutes are critical processes for maintenance of lens homeostasis. Moreover, since there is little turnover or repair of lens proteins, changes in protein structure, including transport proteins, accumulate with age. Our hypothesis is that posttranslational modifications of the lens water channel, MIP, increase with age resulting in impairment of protein function and cataract. The long-term objective of this work is to understand the etiology of senile nuclear cataracts on the molecular level so that prophylactic therapies can be developed. The design of methods for preventing these changes can only begin after i) understanding the changes in protein structure during normal fiber cell maturation, ii) identifying the modifications to lens proteins that are unique to diseased tissue, and iii) determining the structures responsible for impaired function. We propose to identify and quantify age-specific and cataract-specific lens protein modifications and to determine whether those molecular changes cause functional alterations. A multidisciplinary approach, including clinicians and basic scientists, is advanced in this proposal in which state-of-the-art mass spectrometric methods will be employed to characterize structural modifications of lens MIP isolated from aged and cataractous lenses. In addition, molecular biology approaches are presented to test for functional importance of modified residues. Specific aims include: 1) to identify posttranslational modifications in lens MIP isolated from dissected sections from normal lenses, 2) to identify MIP modifications in membranes isolated from clear and opaque tissue from single diseased lenses, and 3) to determine the role of specific modifications in impairment of water permeability. The results of this work are expected to provide new detailed information on the structure and function of the most abundant integral membrane protein in the lens, a critical need in the fundamental understanding of normal lens maturation and senile cataractogenesis.