Insulin, cGMP, and TGF-beta signals regulate food intake and quiescence in C. elegans: a model for satiety

Cell Metab. 2008 Mar;7(3):249-57. doi: 10.1016/j.cmet.2008.01.005.


Despite the prevalence of obesity and its related diseases, the signaling pathways for appetite control and satiety are not clearly understood. Here we report C. elegans quiescence behavior, a cessation of food intake and movement that is possibly a result of satiety. C. elegans quiescence shares several characteristics of satiety in mammals. It is induced by high-quality food, it requires nutritional signals from the intestine, and it depends on prior feeding history: fasting enhances quiescence after refeeding. During refeeding after fasting, quiescence is evoked, causing gradual inhibition of food intake and movement, mimicking the behavioral sequence of satiety in mammals. Based on these similarities, we propose that quiescence results from satiety. This hypothesized satiety-induced quiescence is regulated by peptide signals such as insulin and TGF-beta. The EGL-4 cGMP-dependent protein kinase functions downstream of insulin and TGF-beta in sensory neurons including ASI to control quiescence in response to food intake.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Nutritional Physiological Phenomena
  • Animals
  • Appetite Regulation
  • Caenorhabditis elegans / enzymology
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Cyclic GMP / metabolism*
  • Cyclic GMP-Dependent Protein Kinases / metabolism
  • Eating*
  • Fasting / metabolism
  • Insulin / metabolism*
  • Ion Channels / metabolism
  • Locomotion*
  • Models, Animal
  • Mutation
  • Neurons / metabolism
  • Receptor, Insulin / metabolism
  • Satiety Response*
  • Signal Transduction*
  • Transforming Growth Factor beta / metabolism*


  • Caenorhabditis elegans Proteins
  • DAF-7 protein, C elegans
  • Insulin
  • Ion Channels
  • Transforming Growth Factor beta
  • tax-2 protein, C elegans
  • tax-4 protein, C elegans
  • DAF-2 protein, C elegans
  • Receptor, Insulin
  • Cyclic GMP-Dependent Protein Kinases
  • EGL-4 protein, C elegans
  • Cyclic GMP