TY - JOUR TI - Internal amino acid state modulates yeast taste neurons to support protein homeostasis in Drosophila AU - Steck, Kathrin AU - Walker, Samuel J AU - Itskov, Pavel M AU - Baltazar, Célia AU - Moreira, José-Maria AU - Ribeiro, Carlos A2 - Ramaswami, Mani VL - 7 PY - 2018 DA - 2018/02/02 SP - e31625 C1 - eLife 2018;7:e31625 DO - 10.7554/eLife.31625 UR - https://doi.org/10.7554/eLife.31625 AB - To optimize fitness, animals must dynamically match food choices to their current needs. For drosophilids, yeast fulfills most dietary protein and micronutrient requirements. While several yeast metabolites activate known gustatory receptor neurons (GRNs) in Drosophila melanogaster, the chemosensory channels mediating yeast feeding remain unknown. Here we identify a class of proboscis GRNs required for yeast intake. Within this class, taste peg GRNs are specifically required to sustain yeast feeding. Sensillar GRNs, however, mediate feeding initiation. Furthermore, the response of yeast GRNs, but not sweet GRNs, is enhanced following deprivation from amino acids, providing a potential basis for protein-specific appetite. Although nutritional and reproductive states synergistically increase yeast appetite, reproductive state acts independently of nutritional state, modulating processing downstream of GRNs. Together, these results suggest that different internal states act at distinct levels of a dedicated gustatory circuit to elicit nutrient-specific appetites towards a complex, ecologically relevant protein source. KW - nutrition KW - Taste KW - Behavior KW - Feeding KW - Metabolism KW - calcium imaging JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -