Animals must detect aversive compounds to survive. Bitter taste neurons express heterogeneous combinations of bitter receptors that diversify their response profiles, but this remains poorly understood. Here we describe groups of taste neurons in Drosophila that detect the same bitter compounds using unique combinations of gustatory receptors (GRs). These distinct complexes also confer responsiveness to non-overlapping sets of additional compounds. While either GR32a/GR59c/GR66a or GR22e/GR32a/GR66a heteromultimers are sufficient for lobeline, berberine, and denatonium detection, only GR22e/GR32a/GR66a responds to strychnine. Thus, despite minimal sequence-similarity, Gr22e and Gr59c show considerable but incomplete functional overlap. Since the gain- or loss-of-function of Gr22e or Gr59c alters bitter taste response profiles, we conclude a taste neuron's specific combination of Grs determines its response profile. We suspect the heterogeneity of Gr expression in Drosophila taste neurons diversifies bitter compound detection, improving animal fitness under changing environmental conditions that present a variety of aversive compounds.
Bibliographical noteFunding Information:
We thank the Bloomington Stock Center and Drs H. Amrein and J. Carlson for fly stocks. We thank Dr J. Shim, Mr. J. Choi, Ms. H. S. Choi, and Miss H. Na for helping generate mutants and transgenic flies. This work was supported by a National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MSIP) (NRF-2016R1A5A2008630 and NRF-2012M3A9B2052524 to S.J.M., NRF-2016R1D1A1B03932743 to J.Y.K.).
© 2017 The Author(s).
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Physics and Astronomy(all)