Role of Go/i subgroup of G proteins in olfactory signaling of Drosophila melanogaster.
Intracellular signaling in insect olfactory receptor neurons remains unclear, with both metabotropic and ionotropic components being discussed. Here, we investigated the role of heterotrimeric Go and Gi proteins using a combined behavioral, in vivo and in vitro approach. Specifically, we show that inhibiting Go in sensory neurons by pertussis toxin leads to behavioral deficits. We heterologously expressed the olfactory receptor dOr22a in human embryonic kidney cells (HEK293T). Stimulation with an odor led to calcium influx, which was amplified via calcium release from intracellular stores. Subsequent experiments indicated that the signaling was mediated by the Gβγ subunits of the heterotrimeric Go/i proteins. Finally, using in vivo calcium imaging, we show that Go and Gi contribute to odor responses both for the fast (phasic) as for the slow (tonic) response component. We propose a transduction cascade model involving several parallel processes, in which the metabotropic component is activated by Go and Gi , and uses Gβγ.
Department of Biology, University of Konstanz, D-78457, Konstanz, Germany.
Jennifer S
JS
Ignatious Raja
Natalya
N
Katanayeva
Vladimir L
VL
Katanaev
C Giovanni
CG
Galizia
D000818:Animals; D020013:Calcium Signaling; D029721:Drosophila Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism*; D044387:GTP-Binding Protein beta Subunits / Q000378:metabolism; D044388:GTP-Binding Protein gamma Subunits / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D037342:Pertussis Toxin / Q000494:pharmacology; D011485:Protein Binding; D018035:Receptors, Odorant / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011984:Sensory Receptor Cells / Q000378:metabolism / Q000502:physiology; D012903:Smell
D029721:Drosophila Proteins; C118981:G-protein Beta gamma; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; C496847:OR22a protein, Drosophila; D018035:Receptors, Odorant; D037342:Pertussis Toxin; D019206:GTP-Binding Protein alpha Subunits, Gi-Go
G proteins; insect odorant receptors; olfaction; signaling