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Updated: Jul 10, 2026

Electrophysiological Recording from Drosophila Trichoid Sensilla in Response to Odorants of Low Volatility
Published on: July 27, 2017
Membrane topology of the Drosophila OR83b odorant receptor
Carolina Lundin1, Lukas Käll, Scott A Kreher
1Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, Svante Arrheniusv 12, SE-106 91, Stockholm, Sweden.
Abstract:
By analogy to mammals, odorant receptors (ORs) in insects, such as Drosophila melanogaster, have long been thought to belong to the G-protein coupled receptor (GPCR) superfamily. However, recent work has cast doubt on this assumption and has tentatively suggested an inverted topology compared to the canonical N(out) - C(in) 7 transmembrane (TM) GPCR topology, at least for some Drosophila ORs. Here, we report a detailed topology mapping of the Drosophila OR83b receptor using engineered glycosylation sites as topology markers. Our results are inconsistent with a classical GPCR topology and show that OR83b has an intracellular N-terminus, an extracellular C-terminus, and 7TM helices.
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