Iwahashi Jun, Hamada Nobuyuki, Watanabe Hiroshi
Division of Infectious Diseases, Department of Infectious Medicine, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka 830-0011, Japan.
Biochem Biophys Res Commun. 2007 Apr 6;355(2):508-12. doi: 10.1016/j.bbrc.2007.02.001. Epub 2007 Feb 7.
Reticulon (RTN) proteins are localized to the endoplasmic reticulum (ER), and are related to intracellular membrane trafficking, apoptosis, inhibiting axonal regeneration, and Alzheimer's disease. The RTN proteins are produced without an N-terminal signal peptide. Their C-terminal domain contains two long hydrophobic segments. We analyzed the ER localization signal of human RTN1-A. Mutant proteins lacking the first (39 residues) or second (36 residues) hydrophobic segment showed ER localization. On the other hand, the mutant lacking both hydrophobic segments was cytosolic. Enhanced green fluorescent protein (EGFP) tagged with the first or second hydrophobic segment of RTN1-A was localized to the ER. These results suggest that each hydrophobic segment determines the ER localization. In addition, EGFP tagged with the truncated form of the first hydrophobic segment exhibited the localization to the Golgi rather than the ER. This suggests that the length of the hydrophobic segment contributes to the ER retention of RTN1-A.
网织蛋白（RTN）定位于内质网（ER），与细胞内膜运输、细胞凋亡、抑制轴突再生以及阿尔茨海默病相关。RTN蛋白在没有N端信号肽的情况下产生。它们的C端结构域包含两个长的疏水片段。我们分析了人RTN1-A的内质网定位信号。缺失第一个（39个氨基酸残基）或第二个（36个氨基酸残基）疏水片段的突变蛋白显示出内质网定位。另一方面，缺失两个疏水片段的突变体位于胞质溶胶中。用RTN1-A的第一个或第二个疏水片段标记的增强型绿色荧光蛋白（EGFP）定位于内质网。这些结果表明，每个疏水片段决定内质网定位。此外，用第一个疏水片段的截短形式标记的EGFP定位于高尔基体而非内质网。这表明疏水片段的长度有助于RTN1-A在内质网的滞留。
