title: Identification of Gnr1p, a negative regulator of G alpha signalling in Schizosaccharomyces pombe, and its complementation by human G beta subunits.
abstract: G protein-coupled receptors (GPCRs) are involved in the response of eukaryotic cells to a wide variety of stimuli, traditionally mediating their effects through heterotrimeric G proteins comprised of G alpha, G beta and G gamma subunits. The fission yeast Schizosaccharomyces pombe is an established tool for GPCR research, possessing two G alpha-dependent signalling cascades. A complete G alpha beta gamma complex has been characterised for the glucose-sensing pathway, but only the G alpha subunit, Gpa1p, has been identified in the pheromone-response pathway. Here, we report the use of the yeast two-hybrid system to identify a novel protein, Gnr1p, which interacts with Gpa1p. Gnr1p is predicted to contain seven WD repeats and to adopt a structure similar to typical G beta subunits. Disruption and overexpression studies reveal that Gnr1p negatively regulates the pheromone-response pathway but is not required for signalling. Human G beta subunits complement the loss of Gnr1p, functioning as negative regulators of G alpha signalling in fission yeast.
authors.affiliation: Department of Biological Sciences, University of Warwick, Coventry, UK. A.D.Goddard@warwick.ac.uk
authors.forename: Alan
authors.initials: A
authors.lastname: Goddard
authors.forename: Graham
authors.initials: G
authors.lastname: Ladds
authors.forename: Rachel
authors.initials: R
authors.lastname: Forfar
authors.forename: John
authors.initials: J
authors.lastname: Davey
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D044387:GTP-Binding Protein beta Subunits / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000235:genetics*; D005816:Genetic Complementation Test; D006801:Humans; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques; D009841:Oligonucleotides; D010675:Pheromones / Q000378:metabolism*; D021122:Protein Subunits / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000235:genetics*; D020798:Two-Hybrid System Techniques; D001616:beta-Galactosidase
chemical_list: D044387:GTP-Binding Protein beta Subunits; C516940:Gnr1 protein, S pombe; D009841:Oligonucleotides; D010675:Pheromones; D021122:Protein Subunits; D043562:Receptors, G-Protein-Coupled; D029702:Schizosaccharomyces pombe Proteins; D001616:beta-Galactosidase