title: Expression analysis and subcellular localization of the Arabidopsis thaliana G-protein beta-subunit AGB1.
abstract: Heterotrimeric GTP-binding proteins (G-proteins), consisting of Galpha, Gbeta, and Ggamma subunits, function as molecular switches in many eukaryotic signal transduction pathways. In contrast to many eukaryotes, plants contain very few G-protein subunit isoforms that mediate a diverse array of signalling functions. We investigated the contribution of cell type-specific expression and subcellular localization to this multifunctional signalling capacity for the Arabidopsis thaliana Gbeta subunit, AGB1. Analysis of AGB1 promoter::beta-glucuronidase (GUS) fusions in germinating seeds, seedlings, and flowering plants revealed that AGB1 is widely expressed throughout development in a complex manner. As well as demonstrating similarities to existing Arabidopsis G-protein subunit expression data, several features of the AGB1 expression pattern align closely with known or proposed G-protein functions. A C-terminal AGB1-green fluorescent protein (GFP) fusion was localized at the plasma membrane and in the nucleus of leaf epidermal cells, trichomes and root cells, supporting previous evidence that plant G-protein functionality relies on subcellular compartmentalization.
authors.affiliation: Plant Genetic Engineering Laboratory, School of Integrative Biology, The University of Queensland, St. Lucia, QLD 4072, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Anderson
authors.forename: José R
authors.initials: JR
authors.lastname: Botella
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D015152:Blotting, Northern; D035264:Flowers / Q000378:metabolism; D044387:GTP-Binding Protein beta Subunits / Q000235:genetics* / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D018525:Germination; D005966:Glucuronidase / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D036226:Seedlings / Q000378:metabolism; D012639:Seeds / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: C089590:AGB1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D044387:GTP-Binding Protein beta Subunits; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D005966:Glucuronidase