Obesity-linked homologues TfAP-2 and Twz establish meal frequency in Drosophila melanogaster

PLoS Genet. 2014 Sep 4;10(9):e1004499. doi: 10.1371/journal.pgen.1004499. eCollection 2014 Sep.

Abstract

In all animals managing the size of individual meals and frequency of feeding is crucial for metabolic homeostasis. In the current study we demonstrate that the noradrenalin analogue octopamine and the cholecystokinin (CCK) homologue Drosulfakinin (Dsk) function downstream of TfAP-2 and Tiwaz (Twz) to control the number of meals in adult flies. Loss of TfAP-2 or Twz in octopaminergic neurons increased the size of individual meals, while overexpression of TfAP-2 significantly decreased meal size and increased feeding frequency. Of note, our study reveals that TfAP-2 and Twz regulate octopamine signaling to initiate feeding; then octopamine, in a negative feedback loop, induces expression of Dsk to inhibit consummatory behavior. Intriguingly, we found that the mouse TfAP-2 and Twz homologues, AP-2β and Kctd15, co-localize in areas of the brain known to regulate feeding behavior and reward, and a proximity ligation assay (PLA) demonstrated that AP-2β and Kctd15 interact directly in a mouse hypothalamus-derived cell line. Finally, we show that in this mouse hypothalamic cell line AP-2β and Kctd15 directly interact with Ube2i, a mouse sumoylation enzyme, and that AP-2β may itself be sumoylated. Our study reveals how two obesity-linked homologues regulate metabolic homeostasis by modulating consummatory behavior.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Drosophila Proteins / metabolism*
  • Drosophila melanogaster / metabolism*
  • Drosophila melanogaster / physiology*
  • Feedback
  • Feeding Behavior / physiology*
  • Homeostasis / physiology
  • Hypothalamus / metabolism
  • Male
  • Meals / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Neurons / metabolism
  • Obesity / metabolism*
  • Obesity / physiopathology*
  • Octopamine / metabolism
  • Potassium Channels / metabolism
  • Transcription Factor AP-2 / metabolism

Substances

  • Drosophila Proteins
  • Potassium Channels
  • Transcription Factor AP-2
  • Octopamine

Grants and funding

This study was supported by the Swedish Research Council, as well as the Åhléns Foundation, The Swedish Brain Research Foundation, The National Research Fund of Luxembourg, The Novo Nordisk Foundation, Carl Tryggers Stiftelse, Stiftelsen Olle Engkvist Byggmästare and Lars Hiertas Minne. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.