Champigny G, Imler J L, Puchelle E, Dalemans W, Gribkoff V, Hinnrasky J, Dott K, Barbry P, Pavirani A, Lazdunski M
Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne.
EMBO J. 1995 Jun 1;14(11):2417-23. doi: 10.1002/j.1460-2075.1995.tb07239.x.
The effects of the mild cystic fibrosis (CF) mutation P574H were analysed and compared with those of three severe ones (delta I507, delta F508 and R560T). Immunochemical and functional analyses indicate that the rank order of CFTR expression at the cell surface is: wild type CFTR > P574H >> delta F508 >> R560T approximately 0. Patch-clamp analysis indicates that the open probability of P574H Cl- channels is almost twice as high as that of the wild type CFTR-Cl- channel. This increased intrinsic activity of individual P574H CFTR-Cl- channels compensates for the lower number of P574H CFTR-Cl- channels reaching the cell surface, and probably explains the milder form of CF associated with the P574H mutation. NS004, a recently described activator, restores near normal CFTR activity in cells expressing the P574H-CFTR channel. The P574H mutation modifies the gating mode of the channel with a large increase (approximately x 7) in the mean channel open time. Proline 574 might play an important role in the process connecting ATP hydrolysis at the nucleotide binding domain and opening and closing events of the CFTR-Cl- channel.
分析了轻度囊性纤维化（CF）突变P574H的影响，并与三种严重突变（ΔI507、ΔF508和R560T）的影响进行了比较。免疫化学和功能分析表明，细胞表面CFTR表达的排序为：野生型CFTR > P574H >> ΔF508 >> R560T≈0。膜片钳分析表明，P574H氯离子通道的开放概率几乎是野生型CFTR氯离子通道的两倍。单个P574H CFTR氯离子通道这种内在活性的增加弥补了到达细胞表面的P574H CFTR氯离子通道数量的减少，这可能解释了与P574H突变相关的CF症状较轻的原因。NS004是一种最近描述的激活剂，可在表达P574H-CFTR通道的细胞中恢复接近正常的CFTR活性。P574H突变改变了通道的门控模式，平均通道开放时间大幅增加（约7倍）。脯氨酸574可能在核苷酸结合域的ATP水解与CFTR氯离子通道的开闭事件之间的连接过程中发挥重要作用。
