Price S R, Nightingale M S, Tsuchiya M, Moss J, Vaughan M
National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Mol Cell Biochem. 1996 Jun 7;159(1):15-23. doi: 10.1007/BF00226058.
ADP-ribosylation factors (ARFs) are approximately 20-kDa guanine nucleotide-binding proteins that are allosteric activators of the NAD:arginine ADP-ribosyltransferase activity of cholera toxin and appear to play a role in intracellular vesicular trafficking. Although the physiological roles of these proteins have not been defined, it has been presumed that each has a specific intracellular function. To obtain genetic evidence that each ARF is under evolutionary pressure to maintain its structure, and presumably function, rat ARF cDNA clones were isolated and their nucleotide and deduced amino acid sequences were compared to those of other mammalian ARFs. Deduced amino acid sequences for rat ARFs 1, 2, 3, 5 and 6 were identical to those of the known cognate human and bovine ARFs; rat ARF4 was 96% identical to human ARF4. Nucleotide sequences of both the untranslated as well as the coding regions were highly conserved. These results indicate that the ARF proteins are, as a family, extraordinarily well conserved across mammalian species. The unusually high degree of conservation of the untranslated regions is consistent with these regions having important regulatory roles and that individual ARFs contain structurally unique elements required for specific functions.
ADP核糖基化因子（ARFs）是分子量约为20 kDa的鸟嘌呤核苷酸结合蛋白，是霍乱毒素NAD：精氨酸ADP核糖基转移酶活性的变构激活剂，似乎在细胞内囊泡运输中发挥作用。尽管这些蛋白的生理作用尚未明确，但据推测每种蛋白都具有特定的细胞内功能。为了获得遗传证据，证明每种ARF都处于进化压力之下以维持其结构，并推测还有功能，研究人员分离了大鼠ARF cDNA克隆，并将其核苷酸和推导的氨基酸序列与其他哺乳动物的ARF进行了比较。大鼠ARF 1、2、3、5和6的推导氨基酸序列与已知的同源人类和牛ARF相同；大鼠ARF4与人类ARF4的同源性为96%。非翻译区和编码区的核苷酸序列都高度保守。这些结果表明，作为一个家族，ARF蛋白在哺乳动物物种中异常保守。非翻译区的异常高保守度与这些区域具有重要调节作用一致，并且单个ARF包含特定功能所需的结构独特元件。
