PHOSPHOLIPIDS AS CHEMICAL CHAPERONS FOR CFTR

描述（改编自摘要）：囊性纤维化（CF）是最常见的 在美国流行的常染色体隐性遗传病， 携带突变CFTR基因的人群 这一长期目标 我们的建议是了解突变的CFTR如何在CF中不能正确发挥作用， 患者以及如何修复这些故障。 的deltaF 508突变体， CFTR被保留在内质网（ER）中，从而不能 适当地运输到上皮细胞的顶膜。 而 这种贩运失败的机制可能涉及承认不适当的 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结构域的相互作用 （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 ER滞留和降解，从而引起疾病。 为了验证这一 假设，研究人员提出：1）确定的特异性 磷脂与NBF-1的相互作用以及这种特异性的改变 通过测量与野生型的脂质相互作用， 使用生物物理学测定的突变NBF-1;和2）显示NBF-1诱导 细胞膜的通透性发生变化，而deltaF 508突变改变了细胞膜的通透性。 脂质特异性 该特性将用于开发筛选试验 用于鉴定可能影响CF中突变CFTR运输的药物 患者; 3）显示NBF-1的磷脂特异性的变化 对CFTR在体内的贩运有直接影响。 这一目标将是 通过分析野生型和deltaF 508-CFTR在细胞中的运输， 对脂质生物合成温度敏感的细胞系。 这一建议的重要性在于，它提出了一种新的方法， CF的机制，涉及受磷脂影响的运输缺陷 与突变蛋白的相互作用。 识别这种缺陷可以提供 修复的目标。 如果成功，这种方法将为 开发用于纠正异常相互作用的治疗方法 突变CFTR和特定磷脂之间的联系

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.