Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata. CC 1245, 7600 Mar del Plata, Argentina.
J Exp Bot. 2013 Aug;64(11):3339-49. doi: 10.1093/jxb/ert172.
S-Nitrosylation of Cys residues is one of the molecular mechanisms driven by nitric oxide (NO) for regulating biological functions of key proteins. While the studies on S-nitrosylation of Cys residues have served for identifying SNO proteomes, the physiological relevance of protein S-nitrosylation/denitrosylation remains poorly understood. In this study, it is shown that auxin influences the balance of S-nitrosylated/denitrosylated proteins in roots of Arabidopsis seedlings. 2D-PAGE allowed the identification of ascorbate peroxidase 1 (APX1) as target of auxin-induced denitrosylation in roots. Auxin causes APX1 denitrosylation and partial inhibition of APX1 activity in Arabidopsis roots. In agreement, the S-nitrosylated form of recombinant APX1 expressed in Escherichia coli is more active than the denitrosylated form. Consistently, Arabidopsis apx1 mutants have increased H₂O₂ accumulation in roots, shorter roots, and less sensitivity to auxin than the wild type. It is postulated that an auxin-regulated counterbalance of APX1 S-nitrosylation/denitrosylation contributes to a fine-tuned control of root development and determination of root architecture.
半胱氨酸残基的 S-亚硝基化是一氧化氮（NO）驱动的调节关键蛋白生物功能的分子机制之一。虽然对半胱氨酸残基的 S-亚硝基化研究有助于鉴定 SNO 蛋白质组，但蛋白质 S-亚硝基化/去亚硝基化的生理相关性仍知之甚少。本研究表明，生长素影响拟南芥幼苗根中 S-亚硝基化/去亚硝基化蛋白质的平衡。2D-PAGE 允许鉴定出生长素诱导根中去亚硝基化的抗坏血酸过氧化物酶 1（APX1）作为靶标。生长素导致 APX1 去亚硝基化和 APX1 活性在拟南芥根中的部分抑制。一致地，在大肠杆菌中表达的重组 APX1 的 S-亚硝基化形式比去亚硝基化形式更活跃。一致地，与野生型相比，apx1 突变体在根中积累更多的 H₂O₂，根更短，对生长素的敏感性更低。据推测，生长素调节的 APX1 S-亚硝基化/去亚硝基化的平衡有助于精细控制根发育和决定根结构。
