Moroianu J, Riordan J F
Center for Biochemical and Biophysical Sciences and Medicine, Harvard Medical School, Boston, MA 02115.
Biochem Biophys Res Commun. 1994 Sep 30;203(3):1765-72. doi: 10.1006/bbrc.1994.2391.
Angiogenin is endocytosed by subconfluent endothelial cells, translocated to the nucleus and accumulates in the nucleolus. It also localizes into the nucleolus of digitonin-permeabilized endothelial cells. The peptide RRRGL corresponding to residues 31-35 of human angiogenin specifically targets non-nuclear carrier proteins such as albumin, an anti-human nucleolus monoclonal antibody and R33A angiogenin to the nucleolus of permeabilized endothelial cells. Proteins conjugated with a "mutant" peptide, RRAGL, are not imported. Fluorescein isothiocyanate-conjugated RRRGL is also rapidly imported into the nucleus and localized to the nucleolus, whereas the "mutant" peptide is not. Residue R33 is essential for nuclear translocation and R31 and R32 appear to modulate this process. Thus, 31RRRGL35 is a nuclear localization signal responsible for the nucleolar targeting of human angiogenin.
血管生成素被亚汇合的内皮细胞内吞，转运至细胞核并积聚在核仁中。它也定位于经洋地黄皂苷通透处理的内皮细胞核仁中。对应于人血管生成素第31 - 35位残基的肽RRRGL可将诸如白蛋白、抗人核仁单克隆抗体和R33A血管生成素等非核载体蛋白特异性靶向至通透处理的内皮细胞核仁。与“突变”肽RRAGL缀合的蛋白质不会被导入。异硫氰酸荧光素缀合的RRRGL也会迅速导入细胞核并定位于核仁，而“突变”肽则不会。残基R33对于核转位至关重要，R31和R32似乎调节这一过程。因此，31RRRGL35是负责人类血管生成素核仁靶向的核定位信号。
