title: The stimulatory Gα(s) protein is involved in olfactory signal transduction in Drosophila.
abstract: Seven-transmembrane receptors typically mediate olfactory signal transduction by coupling to G-proteins. Although insect odorant receptors have seven transmembrane domains like G-protein coupled receptors, they have an inverted membrane topology, constituting a key difference between the olfactory systems of insects and other animals. While heteromeric insect ORs form ligand-activated non-selective cation channels in recombinant expression systems, the evidence for an involvement of cyclic nucleotides and G-proteins in odor reception is inconsistent. We addressed this question in vivo by analyzing the role of G-proteins in olfactory signaling using electrophysiological recordings. We found that Gα(s) plays a crucial role for odorant induced signal transduction in OR83b expressing olfactory sensory neurons, but not in neurons expressing CO₂ responsive proteins GR21a/GR63a. Moreover, signaling of Drosophila ORs involved Gα(s) also in a heterologous expression system. In agreement with these observations was the finding that elevated levels of cAMP result in increased firing rates, demonstrating the existence of a cAMP dependent excitatory signaling pathway in the sensory neurons. Together, we provide evidence that Gα(s) plays a role in the OR mediated signaling cascade in Drosophila.
authors.affiliation: Sino-France Joint Center for Drug Research and Screening, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P. R. China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Deng
authors.forename: Weiyi
authors.initials: W
authors.lastname: Zhang
authors.forename: Katja
authors.initials: K
authors.lastname: Farhat
authors.forename: Sonja
authors.initials: S
authors.lastname: Oberland
authors.forename: Günter
authors.initials: G
authors.lastname: Gisselmann
authors.forename: Eva M
authors.initials: EM
authors.lastname: Neuhaus
mesh_terms: D000818:Animals; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D003712:Dendrites / Q000378:metabolism; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D018035:Receptors, Odorant / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D011984:Sensory Receptor Cells / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology
chemical_list: D029721:Drosophila Proteins; D044385:GTP-Binding Protein alpha Subunits; C516369:Gr21a protein, Drosophila; C516368:Gr63a protein, Drosophila; D018035:Receptors, Odorant; D000242:Cyclic AMP