PHOSPHOLIPIDS AS CHEMICAL CHAPERONS FOR CFTR

描述(摘自摘要)：囊性纤维化(CF)是最常见的 美国流行的常染色体隐性致死性遗传病有5% 携带突变cftr基因的人群。这样做的长期目标是 建议是了解突变CFRR如何在CF中无法正常运行 以及如何修复这些故障。的deltaF508突变体 CFTR被保留在内质网(ER)中，因此无法 正确地运输到上皮细胞的顶膜。而当 这一贩运失败的机制可能涉及对不适当的认识 通过蛋白质伴侣折叠CFTR，初步数据表明 磷脂与第一核苷酸结合折叠区的相互作用 (NBF-1)也可能在CFTR贩运中发挥作用。波拉德博士和他的 因此，同事们假设， 突变的NBF-1结构域和特定的磷脂可能有助于 内质网滞留和降解，从而导致疾病。为了测试这一点 假设，研究人员提出：1)确定特异度 磷脂与NBF-1的相互作用及其特异性的改变 通过测量与野生型或野生型的脂质相互作用而导致的deltaF508突变 使用生物物理检测突变体NBF-1；和2)显示NBF-1诱导 膜的通透性改变，而deltaF508突变改变了 脂类专一性。这一特性将被用来开发一种筛查试验 用于识别可能影响CF中突变CFTR贩运的药物 患者；3)显示NBF-1磷脂特异性的变化 对活体内的CFTR贩运有直接后果。这一目标将是 通过分析野生型和DeltaF508-CFTR在细胞内的贩运来探讨 对脂肪生物合成具有温度敏感性的品系。 这项提议的意义在于它提出了一种新的方法来 涉及磷脂影响的转运缺陷的CF机制 与突变蛋白的相互作用。识别这一缺陷可以提供 维修目标。如果成功，这种方法将为 矫正异常相互作用的治疗手段的发展 突变的cftr和特定的磷脂之间的关系。

DESCRIPTION (adapted from abstract): Cystic fibrosis (CF) is the most prevalent autosomal recessive lethal genetic disease in the U.S. with 5% of the population carrying a mutant CFTR gene. The long term goals of this proposal are to understand how mutant CFTRs fail to function correctly in CF patients and how these failures might be repaired. The deltaF508 mutant of CFTR is retained in the endoplasmic reticulum (ER) and thereby fails to traffic properly to the apical membrane of epithelial cells. While the mechanism of this trafficking failure may involve recognition of improperly folded CFTR by protein chaperones, preliminary data indicate that phospholipid interactions with the first nucleotide binding fold domain (NBF-1) might also play a role in CFTR trafficking. Dr. Pollard and his colleagues have therefore hypothesized that aberrant interactions between the mutant NBF-1 domain and specific phospholipids might contribute to the ER retention and degradation, and thus cause the disease. To test this hypothesis, the investigators propose: 1) to determine the specificity of phospholipid interaction with NBF-1 and the alteration of this specificity by the deltaF508 mutation by measuring lipid interaction with wild type or mutant NBF-1 using biophysical assays; and 2) to show that NBF-1 induces permeability changes in membranes, and that deltaF508 mutation changes the lipid specificity. This property will be used to develop a screening assay for identifying drugs that might affect mutant CFTR trafficking in CF patients; 3) to show that changes in the phospholipid specificity of NBF-1 have direct consequences for CFTR trafficking in vivo. This aim will be approached by analyzing wild type and deltaF508-CFTR trafficking in a cell line which is temperature sensitive for lipid biosynthesis. The significance of this proposal is that it suggests a novel approach to the mechanism of CF, involving a trafficking defect affected by phospholipid interactions with the mutant protein. Identifying this defect can provide targets for repair. If successful, this approach will set the stage for development of therapeutic means for correcting the aberrant interactions between mutant CFTR and specific phospholipids.