Rotoli B M, Bussolati O, Sironi M, Cabrini G, Gazzola G C
Istituto di Patologia Generale, Università degli Studi di Parma, Italy.
Biochem Biophys Res Commun. 1994 Oct 28;204(2):653-8. doi: 10.1006/bbrc.1994.2509.
Trans-membrane fluxes of leucine were measured in mouse C127i cells transfected with the wild type (C127 CFTRw/t) or the delta F508 CF gene (C127 CFTR delta F508). Leucine efflux was significantly faster in C127 CFTRw/t cells. On the contrary, leucine influx was comparable in the two cell lines and referable to a "L-type" transport system. No significant differences in leucine content were detected among the two cell lines when maintained in complete growth medium; in contrast, after prolonged incubation in amino-acid-free saline solution, the amount of intracellular leucine was significantly smaller in C127 CFTRw/t than in C127 CFTR delta F508 cells. Leucine behavior was shared by other neutral amino acids with non polar side chains. These results suggest that the expression of normal CFTR increases the efflux of a subgroup of neutral amino acids.
在转染了野生型（C127 CFTRw/t）或ΔF508 CF基因（C127 CFTR ΔF508）的小鼠C127i细胞中测量了亮氨酸的跨膜通量。亮氨酸外流在C127 CFTRw/t细胞中明显更快。相反，亮氨酸内流在这两种细胞系中相当，且归因于一种“L型”转运系统。当在完全生长培养基中培养时，在这两种细胞系之间未检测到亮氨酸含量的显著差异；相比之下，在无氨基酸盐溶液中长时间孵育后，C127 CFTRw/t细胞中细胞内亮氨酸的量明显少于C127 CFTR ΔF508细胞。亮氨酸的这种行为也存在于其他具有非极性侧链的中性氨基酸中。这些结果表明，正常CFTR的表达增加了一组中性氨基酸的外流。
