期刊
INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE
卷 51, 期 8, 页码 4164-4173出版社
ASSOC RESEARCH VISION OPHTHALMOLOGY INC
DOI: 10.1167/iovs.09-4087
关键词
-
资金
- National Institutes of Health [EY13250, EY012239, EY011717]
- Johnson Johnson
- American Health Assistance Foundation
- United States Department of Agriculture [1950-510000-060-01a]
PURPOSE. The accumulation, aggregation, and precipitation of proteins is etiologic for age-related diseases, particularly cataract, because the precipitates cloud the lens. Deamidation of crystallins is associated with protein precipitation, aging, and cataract. Among the roles of the ubiquitin proteasome pathway (UPP) is protein surveillance and maintenance of protein quality. The purpose of this study was to determine whether deamidation can alter clearance of crystallins by the UPP. METHODS. Wild-type (WT) and deamidated crystallins were expressed and I-125-radiolabeled. Ubiquitination and degradation were monitored separately. RESULTS. For beta B2 crystallins, rates of ubiquitination and adenosine triphosphate-dependent degradation, both indicators of active UPP, occurred in the order Q70E/Q162E>Q162E> Q70E = WT beta B2 using reticulocyte lysate as the source of degradation machinery. Human lens epithelial cell lysates and lens fiber cell lysates also catalyzed ubiquitination but only limited degradation. Supplementation with proteasome failed to enhance degradation. Rates of ubiquitination and degradation of WT and deamidated beta B1 crystallins were rapid and showed little relationship to the site of deamidation using N157D and Q204E mutants. gamma D-Crystallins were not degraded by the UPP. Deamidation altered amine reactivity, circular dichroism spectra, surface hydrophobicity, and thermal stability. CONCLUSIONS. These data demonstrate for the first time that, like mild oxidative stress, deamidation of some proteins makes them preferred substrates for ubiquitination and, in some cells, for UPP-dependent degradation. Failure to properly execute ubiquitination and degrade the ubiquitin-conjugates may ex-plain their accumulation on aging and in cataractogenesis. (Invest Ophthalmol Vis Sci. 2010;51:4164-4173) DOI:10.1167/iovs.09-4087
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据