title: Gsalpha is involved in sugar perception in Drosophila melanogaster.
abstract: In Drosophila melanogaster, gustatory receptor genes (Grs) encode G-protein-coupled receptors (GPCRs) in gustatory receptor neurons (GRNs) and some olfactory receptor neurons. One of the Gr genes, Gr5a, encodes a sugar receptor that is expressed in a subset of GRNs and has been most extensively studied both molecularly and physiologically, but the G-protein alpha subunit (Galpha) that is coupled to this sugar receptor remains unknown. Here, we propose that Gs is the Galpha that is responsible for Gr5a-mediated sugar-taste transduction, based on the following findings: First, immunoreactivities against Gs were detected in a subset of GRNs including all Gr5a-expressing neurons. Second, trehalose-intake is reduced in flies heterozygous for null mutations in DGsalpha, a homolog of mammalian Gs, and trehalose-induced electrical activities in sugar-sensitive GRNs were depressed in those flies. Furthermore, expression of wild-type DGsalpha in sugar-sensitive GRNs in heterozygotic DGsalpha mutant flies rescued those impairments. Third, expression of double-stranded RNA for DGsalpha in sugar-sensitive GRNs depressed both behavioral and electrophysiological responses to trehalose. Together, these findings indicate that DGsalpha is involved in trehalose perception. We suggest that sugar-taste signals are processed through the Gsalpha-mediating signal transduction pathway in sugar-sensitive GRNs in Drosophila.
authors.affiliation: Department of Behavioral Sciences, Graduate School of Medicine, Gunma University, Maebashi 371-8511, Japan. kueno@med.gunma-u.ac.jp
authors.forename: Kohei
authors.initials: K
authors.lastname: Ueno
authors.forename: Soh
authors.initials: S
authors.lastname: Kohatsu
authors.forename: Catherine
authors.initials: C
authors.lastname: Clay
authors.forename: Michael
authors.initials: M
authors.lastname: Forte
authors.forename: Kunio
authors.initials: K
authors.lastname: Isono
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kidokoro
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001522:Behavior, Animal / Q000502:physiology; D002241:Carbohydrates; D029721:Drosophila Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004331:Drosophila melanogaster; D004435:Eating / Q000502:physiology; D004594:Electrophysiology; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000502:physiology*; D015870:Gene Expression; D006579:Heterozygote; D009154:Mutation; D009475:Neurons, Afferent / Q000378:metabolism / Q000502:physiology; D054799:Phospholipase C beta; D020033:Protein Isoforms / Q000378:metabolism; D034622:RNA Interference; D011956:Receptors, Cell Surface / Q000172:deficiency / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D013649:Taste / Q000502:physiology*; D019076:Transgenes; D014199:Trehalose; D010738:Type C Phospholipases / Q000172:deficiency / Q000235:genetics
chemical_list: D002241:Carbohydrates; D029721:Drosophila Proteins; D020033:Protein Isoforms; D011956:Receptors, Cell Surface; C405956:gustatory receptor, Drosophila; D014199:Trehalose; D010738:Type C Phospholipases; C468371:NorpA protein, Drosophila; D054799:Phospholipase C beta; D019205:GTP-Binding Protein alpha Subunits, Gs