THE ROLE OF LENS MIP IN AGING AND CATARACTOGENESIS

晶状体 MIP 在老化和白内障发生中的作用

• 批准号: 6518726
• 负责人: Kevin L Schey
• 金额: $ 21.45万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-05-01 至 2005-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6518726
• 关键词: Xenopus oocyte; aging; amination; calcium binding protein; cataract; disease /disorder etiology; fiber cell; high performance liquid chromatography; human tissue; immunocytochemistry; lens proteins; mass spectrometry; membrane proteins; molecular pathology; phosphorylation; posttranslational modifications; protein structure function; water channel; western blottings

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.

描述（由申请人提供）：人类透镜用作紫外线过滤器， 将光线聚焦到视网膜上。透明度和高折射率是关键 允许透镜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的包装和蛋白质 溶解度由于透镜缺乏血液供应，水的运输， 离子和中性溶质是维持透镜的关键过程 体内平衡此外，由于透镜的翻转或修复很少， 蛋白质，蛋白质结构的变化，包括转运蛋白， 随着年龄的积累。我们的假设是， 透镜水通道MIP随年龄增长而增加， 蛋白质功能和白内障。这项工作的长期目标是 从分子水平上了解老年性核性白内障的病因， 预防性治疗是可以发展的。方法的设计 防止这些变化只能开始后，i）了解的变化， 正常纤维细胞成熟过程中的蛋白质结构，ii）鉴定 对患病组织特有的透镜蛋白的修饰，和iii） 确定导致功能受损的结构。我们建议 鉴定和定量年龄特异性和白内障特异性透镜蛋白 修饰，并确定这些分子变化是否会导致功能性 改变。 包括临床医生和基础科学家在内的多学科方法， 先进的质谱方法 将用于表征分离的透镜MIP的结构修饰 从老化和白内障的晶状体。此外，分子生物学方法是 以测试修饰残基的功能重要性。具体目标 包括：1）鉴定分离透镜MIP中的翻译后修饰 从正常晶状体的解剖切片中，2）识别 从单个患病晶状体的透明和不透明组织分离的膜， 和3）确定特定修饰在水损害中的作用 磁导率这项工作的结果预计将提供新的详细的 最丰富积分的结构和函数信息 透镜中的膜蛋白，这是基本理解 正常的透镜成熟和老年性白内障。