Poornima V, Vallabhaneni Sirisha, Mukhopadhyay Mohona, Bera Amal Kanti
Department of Biotechnology, Bhupat & Jyoti Mehta School of BioSciences, Indian Institute of Technology Madras, Sardar Patel Road, Chennai, Tamil Nadu 600036, India.
Department of Biotechnology, Bhupat & Jyoti Mehta School of BioSciences, Indian Institute of Technology Madras, Sardar Patel Road, Chennai, Tamil Nadu 600036, India.
Nitric Oxide. 2015 May 1;47:77-84. doi: 10.1016/j.niox.2015.04.005. Epub 2015 Apr 23.
Nitric oxide (NO), a major gaseous signaling molecule, modulates several ion channels and receptors. Here we show that NO attenuates pannexin 1 (Panx1) mediated currents in HEK-293 cells. NO exerts its effect by activating a cGMP-protein kinase G (PKG) dependent pathway. NO donors, sodium nitroprusside (SNP), S-nitroso-N-acetylpenicillamine (SNAP) and S-nitrosoglutathione (GSNO), reduced Panx1 currents by 25-41%. 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), an inhibitor of soluble guanylyl cyclase (sGC), blocked the inhibition completely, whereas sGC activator YC-1 mimicked the effect of NO, suggesting the involvement of a cGMP dependent pathway. Supporting this, NO had no effect in the presence of the PKG inhibitor, KT5823. Further, immuno-precipitated Panx1 was recognized by an anti-phosphoserine antibody in Western blot. Phosphorylation was enhanced significantly when cells were treated with SNP. The target for phosphorylation is possibly Ser 206 of Panx1, as its mutation to Ala completely abolished the NO mediated inhibition.
一氧化氮（NO）是一种主要的气体信号分子，可调节多种离子通道和受体。在此我们表明，NO可减弱HEK - 293细胞中pannexin 1（Panx1）介导的电流。NO通过激活环磷酸鸟苷 - 蛋白激酶G（PKG）依赖性途径发挥其作用。NO供体硝普钠（SNP）、S - 亚硝基 - N - 乙酰青霉胺（SNAP）和S - 亚硝基谷胱甘肽（GSNO）使Panx1电流降低了25% - 41%。可溶性鸟苷酸环化酶（sGC）抑制剂1H - [1,2,4]恶二唑并[4,3 - a]喹喔啉 - 1 - 酮（ODQ）完全阻断了这种抑制作用，而sGC激活剂YC - 1模拟了NO的作用，表明涉及cGMP依赖性途径。支持这一点的是，在PKG抑制剂KT5823存在的情况下，NO没有作用。此外，免疫沉淀的Panx1在蛋白质印迹中可被抗磷酸丝氨酸抗体识别。当用SNP处理细胞时，磷酸化显著增强。磷酸化的靶点可能是Panx1的丝氨酸206，因为将其突变为丙氨酸完全消除了NO介导的抑制作用。
