Rennolds Jessica, Boyaka Prosper N, Bellis Susan L, Cormet-Boyaka Estelle
Department of Internal Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, 201 Davis Heart and Lung Research Institute, 473 West 12th Avenue, Columbus, OH 43210-1252, USA.
Biochem Biophys Res Commun. 2008 Feb 22;366(4):1025-9. doi: 10.1016/j.bbrc.2007.12.065. Epub 2007 Dec 26.
Deletion of phenylalanine 508 (DeltaF508) is the most prevalent disease-causing mutation resulting in retention of the immature CFTR in the endoplasmic reticulum. The most common strategy to induce the delivery of DeltaF508-CFTR to the surface of cells is by reducing the incubation temperature ( approximately 28 degrees C). Cell surface biotinylation of HEK293T cells grown at 37 degrees C for 48h, confirmed the presence of mature wild-type CFTR, but not DeltaF508-CFTR at the cell surface. On the other hand, cells incubated at 28 degrees C for 16h showed both mature and immature DeltaF508-CFTR at their surface. The trafficking of immature DeltaF508-CFTR, but not mature DeltaF508-CFTR, to the cell surface occurred at low temperature even upon addition of BFA, suggesting the involvement of a Golgi-independent pathway. These results suggest that low temperature induces the appearance of a mix population of mature and immature CFTR molecules at the plasma membrane through distinct pathways.
苯丙氨酸508缺失（ΔF508）是最常见的致病突变，会导致未成熟的囊性纤维化跨膜传导调节因子（CFTR）滞留在内质网中。诱导ΔF508 - CFTR转运至细胞表面的最常用策略是降低孵育温度（约28摄氏度）。在37摄氏度下培养48小时的人胚肾293T（HEK293T）细胞进行细胞表面生物素化，证实细胞表面存在成熟的野生型CFTR，但不存在ΔF508 - CFTR。另一方面，在28摄氏度下孵育16小时的细胞表面同时存在成熟和未成熟的ΔF508 - CFTR。即使添加了布雷菲德菌素A（BFA），未成熟的ΔF508 - CFTR而非成熟的ΔF508 - CFTR在低温下仍会转运至细胞表面，这表明存在一条不依赖高尔基体的途径。这些结果表明，低温通过不同途径诱导质膜上出现成熟和未成熟CFTR分子的混合群体。
