title: ABA-dependent and -independent G-protein signaling in Arabidopsis roots revealed through an iTRAQ proteomics approach.
abstract: Heterotrimeric G-proteins are important signal transducers in all eukaryotes. The plant hormone abscisic acid (ABA) has emerged as a key regulator of G-protein-mediated signaling pathways in plants. ABA-regulation of G-protein signaling involves both conventional and novel mechanisms. We have utilized the null mutant of the Arabidopsis G-protein α subunit gpa1 to evaluate to what extent ABA-dependent changes in the proteome are regulated by G-proteins. We used Arabidopsis root tissue as both ABA and G-proteins, individually and in combination, affect root growth and development. We identified 720 proteins, of which 42 showed GPA1-dependent and 74 showed ABA-dependent abundance changes. A majority of ABA-regulated proteins were also GPA1-dependent. Our data provide insight into how tissue specificity might be achieved in ABA-regulated G-protein signaling. A number of proteins related to ER body formation and intracellular trafficking were altered in gpa1 mutant, suggesting a novel role for GPA1 in these pathways. A potential link between ABA metabolism and ABA signaling was also revealed. The comparison of protein abundance changes in the absence of ABA offers clues to the role of GPA1 in ABA-independent signaling pathways, for example, regulation of cell division. These findings substantially contribute to our knowledge of G-protein signaling mechanisms in plants.
authors.affiliation: Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, Missouri 63132, USA.
authors.forename: Sophie
authors.initials: S
authors.lastname: Alvarez
authors.forename: Leslie M
authors.initials: LM
authors.lastname: Hicks
authors.forename: Sona
authors.initials: S
authors.lastname: Pandey
mesh_terms: D000040:Abscisic Acid / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D002853:Chromatography, Liquid; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D010937:Plant Growth Regulators / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D030821:Plants, Genetically Modified; D040901:Proteomics / Q000379:methods*; D015398:Signal Transduction / Q000235:genetics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013194:Staining and Labeling / Q000379:methods*; D053719:Tandem Mass Spectrometry
chemical_list: D029681:Arabidopsis Proteins; C429765:GPA1 protein, Arabidopsis; D044385:GTP-Binding Protein alpha Subunits; D010937:Plant Growth Regulators; D000040:Abscisic Acid