Zerhusen B, Ma J
Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH, USA.
FEBS Lett. 1999 Oct 8;459(2):177-85. doi: 10.1016/s0014-5793(99)01230-2.
To test the role of nucleotide-binding fold (NBF) 2 and its interaction with the regulatory (R) domain in the function of the cystic fibrosis transmembrane conductance regulator (CFTR) channel, we used three deletion mutants of CFTR: DeltaR(708-835), DeltaNBF2(1185-1349) and DeltaR-DeltaNBF2. In lipid bilayers, DeltaNBF2 channel activity is ATP- and cAMP-dependent protein kinase (PKA)-dependent, but unlike wild-type (wt) CFTR, it displays a reduced activity and insensitivity to 5'-adenylylimidodiphosphate (AMP-PNP). Both DeltaR and DeltaR-DeltaNBF2 channels are PKA-independent, but DeltaR activity is reduced whereas DeltaR-DeltaNBF2 activity is increased. Deletion of NBF2 from CFTR affects protein trafficking and channel gating kinetics. The data suggest that NBF2 could have inhibitory and stimulatory roles in CFTR activity by interaction with NBF1 directly or indirectly via the R domain.
为了测试核苷酸结合结构域（NBF）2及其与调节（R）结构域的相互作用在囊性纤维化跨膜传导调节因子（CFTR）通道功能中的作用，我们使用了CFTR的三个缺失突变体：DeltaR(708 - 835)、DeltaNBF2(1185 - 1349)和DeltaR - DeltaNBF2。在脂质双分子层中，DeltaNBF2通道活性依赖于ATP和环磷酸腺苷（cAMP）依赖性蛋白激酶（PKA），但与野生型（wt）CFTR不同，它表现出活性降低且对5'-腺苷酰亚胺二磷酸（AMP-PNP）不敏感。DeltaR和DeltaR - DeltaNBF2通道均不依赖PKA，但DeltaR活性降低而DeltaR - DeltaNBF2活性增加。从CFTR中缺失NBF2会影响蛋白质转运和通道门控动力学。数据表明，NBF2可能通过直接与NBF1相互作用或经由R结构域间接与NBF1相互作用，在CFTR活性中发挥抑制和刺激作用。
