title: The phosphoproteome of Arabidopsis plants lacking the oxidative signal-inducible1 (OXI1) protein kinase.
abstract: The AGC protein kinase OXI1 is a key protein in plant responses to oxidative signals, and is important for two oxidative burst-mediated processes: basal resistance to microbial pathogens and root hair growth. To identify possible components of the OXI1 signalling pathway, phosphoproteomic techniques were used to detect alterations in the abundance of phosphorylated proteins and peptides in an oxi1 null mutant of Arabidopsis thaliana. The relative abundance of phosphorylated proteins was assessed either using two-dimensional gel electrophoresis and staining with the phosphoprotein stain Pro-Q Diamond or by the identification and quantification, by mass spectrometry, of stable-isotope labelled phosphopeptides. A number of proteins show altered phosphorylation in the oxi1 mutant. Five proteins, including a putative F-box and 3-phosphoinositide-dependent kinase 1, show reduced phosphorylation in the oxi1 mutant, and may be direct or indirect targets of OXI1. Four proteins, including ethylene insensitive 2 and phospholipase d-gamma, show increased phosphorylation in the oxi1 mutant. This study has identified a range of candidate proteins from the OXI1 signalling pathway. The diverse activities of these proteins, including protein degradation and hormone signalling, may suggest crosstalk between OXI1 and other signal transduction cascades.
authors.affiliation: Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK.
authors.forename: Andrew J M
authors.initials: AJM
authors.lastname: Howden
authors.affiliation: Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK.
authors.forename: Mogjiborahman
authors.initials: M
authors.lastname: Salek
authors.affiliation: Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK.
authors.forename: Laurent
authors.initials: L
authors.lastname: Miguet
authors.affiliation: Plant Stress Signalling Laboratory, School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE, UK.
authors.forename: Margaret
authors.initials: M
authors.lastname: Pullen
authors.affiliation: Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Thomas
authors.affiliation: Plant Stress Signalling Laboratory, School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE, UK.
authors.forename: Marc R
authors.initials: MR
authors.lastname: Knight
authors.affiliation: Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK.
authors.forename: Lee J
authors.initials: LJ
authors.lastname: Sweetlove
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000378:metabolism*; D002853:Chromatography, Liquid; D015180:Electrophoresis, Gel, Two-Dimensional; D007553:Isotope Labeling; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D010748:Phosphopeptides / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000378:metabolism*; D020543:Proteome / Q000737:chemistry / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D050505:Mutant Proteins; D010748:Phosphopeptides; D020543:Proteome; C482589:OXI1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases