Sawa Tomohiro, Zaki Mohammad Hasan, Okamoto Tatsuya, Akuta Teruo, Tokutomi Yoshiko, Kim-Mitsuyama Shokei, Ihara Hideshi, Kobayashi Akira, Yamamoto Masayuki, Fujii Shigemoto, Arimoto Hirokazu, Akaike Takaaki
Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
Nat Chem Biol. 2007 Nov;3(11):727-35. doi: 10.1038/nchembio.2007.33. Epub 2007 Sep 30.
The signaling pathway of nitric oxide (NO) depends mainly on guanosine 3',5'-cyclic monophosphate (cGMP). Here we report the formation and chemical biology of a nitrated derivative of cGMP, 8-nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP), in NO-mediated signal transduction. Immunocytochemistry demonstrated marked 8-nitro-cGMP production in various cultured cells in an NO-dependent manner. This finding was confirmed by HPLC plus electrochemical detection and tandem mass spectrometry. 8-Nitro-cGMP activated cGMP-dependent protein kinase and showed unique redox-active properties independent of cGMP activity. Formation of protein Cys-cGMP adducts by 8-nitro-cGMP was identified as a new post-translational modification, which we call protein S-guanylation. 8-Nitro-cGMP seems to regulate the redox-sensor signaling protein Keap1, via S-guanylation of the highly nucleophilic cysteine sulfhydryls of Keap1. This study reveals 8-nitro-cGMP to be a second messenger of NO and sheds light on new areas of the physiology and chemical biology of signal transduction by NO.
一氧化氮（NO）的信号通路主要依赖于3',5'-环磷酸鸟苷（cGMP）。在此，我们报告了cGMP的一种硝化衍生物8-硝基-3',5'-环磷酸鸟苷（8-硝基-cGMP）在NO介导的信号转导中的形成及其化学生物学特性。免疫细胞化学显示，在各种培养细胞中，8-硝基-cGMP以NO依赖的方式大量产生。这一发现通过高效液相色谱结合电化学检测和串联质谱得到了证实。8-硝基-cGMP激活了cGMP依赖性蛋白激酶，并表现出独立于cGMP活性的独特氧化还原活性特性。8-硝基-cGMP形成蛋白半胱氨酸-cGMP加合物被鉴定为一种新的翻译后修饰，我们将其称为蛋白S-鸟苷化。8-硝基-cGMP似乎通过对Keap1高度亲核的半胱氨酸巯基进行S-鸟苷化来调节氧化还原传感器信号蛋白Keap1。这项研究揭示了8-硝基-cGMP是NO的第二信使，并为NO信号转导的生理学和化学生物学新领域提供了线索。
