8-Nitro-cGMP Enhances SNARE Complex Formation through S-Guanylation of Cys90 in SNAP25

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• 作者：Kohei Kunieda ; Hiroyasu Tsutsuki ; Tomoaki Ida ; Yusuke Kishimoto ; Shingo Kasamatsu ; Tomohiro Sawa ; Naoki Goshima ; Makoto Itakura ; Masami Takahashi ; Takaaki Akaike ; Hideshi Ihara
• 刊名：ACS Chemical Neuroscience
• 出版年：2015
• 出版时间：October 21, 2015
• 年：2015
• 卷：6
• 期：10
• 页码：1715-1725
• 全文大小：514K
• ISSN：1948-7193

文摘

Nitrated guanine nucleotide 8-nitroguanosine 3鈥?5鈥?cyclic monophosphate (8-nitro-cGMP) generated by reactive oxygen/nitrogen species causes protein S-guanylation. However, the mechanism of 8-nitro-cGMP formation and its protein targets in the normal brain have not been identified. Here, we investigated 8-nitro-cGMP generation and protein S-guanylation in the rodent brain. Immunohistochemistry indicated that 8-nitro-cGMP was produced by neurons, such as pyramidal cells and interneurons. Using liquid chromatography-tandem mass spectrometry, we determined endogenous 8-nitro-cGMP levels in the brain as 2.92 卤 0.10 pmol/mg protein. Based on S-guanylation proteomics, we identified several S-guanylated neuronal proteins, including SNAP25 which is a core member of the soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) complex. SNAP25 post-translational modification including palmitoylation, phosphorylation, and oxidation, are known to regulate neurotransmission. Our results demonstrate that S-guanylation of SNAP25 enhanced the stability of the SNARE complex, which was further promoted by Ca²⁺-dependent activation of neuronal nitric oxide synthase. Using site-directed mutagenesis, we identified SNAP25 cysteine 90 as the main target of S-guanylation which enhanced the stability of the SNARE complex. The present study revealed a novel target of redox signaling via protein S-guanylation in the nervous system and provided the first substantial evidence of 8-nitro-cGMP function in the nervous system.