A defective flexible loop contributes to the processing and gating defects of the predominant cystic fibrosis-causing mutation
A defective flexible loop contributes to the processing and gating defects of the predominant cystic fibrosis-causing mutation
复制标题
有缺陷的柔性环导致主要囊性纤维化突变的加工和门控缺陷
DOI：
10.1096/fj.201801218rr
复制
发表时间：
2019-04-01
期刊：
影响因子：
4.8
通讯作者：
Chen, Jeng-Haur
中科院分区：
文献类型：
--
作者：
Chen, Xinying;Zhu, Siyu;Chen, Jeng-Haur
患有遗传性疾病囊性纤维化（CF）的人通常在编码CF跨膜传导调节因子（CFTR）Cl-通道的基因上携带缺失突变Delta F508。这种突变大大减少了CFTR成熟过程，并减缓了通道开放速率。在这里，我们研究F508附近的残基是否有助于Delta F508-CFTR中的这些缺陷。大多数缺失突变，但不是丙氨酸取代，从位置503至513的单个残基损害CFTR成熟。有趣的是，只有Delta Y512-CFTR的蛋白质加工，如Delta F508-CFTR的蛋白质加工，通过27 ℃的低温培养或小分子校正剂C18大大改善。2个突变的Cl-通道同样缓慢打开，表明它们可能具有共同的结构缺陷。对连接残基F508和Y512的H3-H4环的研究表明，G509 A/V510 G突变，在环中向后移动G509 1位置，显著增强Delta F508-CFTR成熟和打开速率，同时促进Delta F508核苷酸结合结构域1中H3螺旋的蛋白质稳定性和持久性。此外，V510 A/S511 A突变显著增加了Delta Y512-CFTR在27 ° C下的成熟及其开放速率。因此，环路异常可能导致Delta F508-和Delta Y512-CFTR缺陷。重要的是，在Delta F508-CFTR中纠正G509置换的缺陷可能为药物发现和CF治疗提供新的途径。
People with the genetic disease cystic fibrosis (CF) often carry a deletion mutation Delta F508 on the gene encoding the CF transmembrane conductance regulator (CFTR) Cl- channel. This mutation greatly reduces the CFTR maturation process and slows the channel opening rate. Here, we investigate whether residues near F508 contribute to these defects in Delta F508-CFTR. Most deletion mutations, but not alanine substitutions, of individual residues from positions 503 to 513 impaired CFTR maturation. Interestingly, only protein processing of Delta Y512-CFTR, like that of Delta F508-CFTR, was greatly improved by low-temperature culture at 27 degrees C or small-molecule corrector C18. The 2 mutant Cl- channels were equally slow to open, suggesting that they may share common structural flaws. Studies on the H3-H4 loop that links residues F508 and Y512 demonstrate that G509A/V510G mutations, moving G509 1 position backward in the loop, markedly enhanced Delta F508-CFTR maturation and opening rate while promoting protein stability and persistence of the H3 helix in Delta F508 nucleotide-binding domain 1. Moreover, V510A/S511A mutations noticeably increased Delta Y512-CFTR maturation at 27 degrees C and its opening rate. Thus, loop abnormalities may contribute to Delta F508- and Delta Y512-CFTR defects. Importantly, correcting defects from G509 displacement in Delta F508-CFTR may offer a new avenue for drug discovery and CF treatments.