title: Auxin induces redox regulation of ascorbate peroxidase 1 activity by S-nitrosylation/denitrosylation balance resulting in changes of root growth pattern in Arabidopsis.
abstract: 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.
authors.affiliation: Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata. CC 1245, 7600 Mar del Plata, Argentina.
authors.forename: Natalia
authors.initials: N
authors.lastname: Correa-Aragunde
authors.forename: Noelia
authors.initials: N
authors.lastname: Foresi
authors.forename: Massimo
authors.initials: M
authors.lastname: Delledonne
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Lamattina
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D060387:Ascorbate Peroxidases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D007210:Indoleacetic Acids / Q000494:pharmacology*; D010084:Oxidation-Reduction / Q000187:drug effects*; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D060387:Ascorbate Peroxidases
keywords: Arabidopsis; S-nitrosylation; ascorbate peroxidase 1; auxin; nitric oxide; root.