title: A novel proteomic approach reveals a role for Mg-protoporphyrin IX in response to oxidative stress.
abstract: The presence of genes encoding organellar proteins in different cellular compartments necessitates a tight coordination of expression by the different genomes of the eukaryotic cell. This coordination of gene expression is achieved by organelle-to-nucleus communication. Stress-induced perturbations of the tetrapyrrole pathway trigger large changes in nuclear gene expression. In order to investigate whether the tetrapyrrole Mg-ProtoIX itself is an important part of plastid-to-nucleus communication, we used an affinity column containing Mg-ProtoIX covalently linked to an Affi-Gel matrix. The proteins that bound to Mg-ProtoIX were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis combined with nano liquid chromatography-mass spectrometry (MS)/MS. Thus, we present a novel proteomic approach to address the mechanisms involved in cellular signaling and we identified interactions between Mg-ProtoIX and a large number of proteins associated with oxidative stress responses. Our approach revealed an interaction between Mg-ProtoIX and the heat shock protein 90-type protein, HSP81-2 suggesting that a regulatory complex including HSP90 proteins and tetrapyrroles controlling gene expression is evolutionarily conserved between yeast and plants. In addition, our list of putative Mg-ProtoIX-binding proteins demonstrated that binding of tetrapyrroles does not depend on a specific amino acid motif but possibly on a specific fold of the protein.
authors.affiliation: Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, SE-901 87 Umeå, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Kindgren
authors.forename: Mats-Jerry
authors.initials: MJ
authors.lastname: Eriksson
authors.forename: Catherine
authors.initials: C
authors.lastname: Benedict
authors.forename: Anasuya
authors.initials: A
authors.lastname: Mohapatra
authors.forename: Simon P
authors.initials: SP
authors.lastname: Gough
authors.forename: Mats
authors.initials: M
authors.lastname: Hansson
authors.forename: Thomas
authors.initials: T
authors.lastname: Kieselbach
authors.forename: Asa
authors.initials: A
authors.lastname: Strand
mesh_terms: D020816:Amino Acid Motifs; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D019295:Computational Biology; D018506:Gene Expression Regulation, Plant; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism; D008190:Lyases / Q000378:metabolism; D018384:Oxidative Stress; D011485:Protein Binding; D021122:Protein Subunits / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D011524:Protoporphyrins / Q000378:metabolism*; D015203:Reproducibility of Results; D015398:Signal Transduction; D013050:Spectrometry, Fluorescence; D013312:Stress, Physiological; D045725:Tetrapyrroles / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D045342:Light-Harvesting Protein Complexes; D021122:Protein Subunits; D011524:Protoporphyrins; D045725:Tetrapyrroles; C039629:magnesium protoporphyrin; C028025:protoporphyrin IX; D008190:Lyases; C086788:magnesium chelatase