molecular basis for water taste in Drosophila

• Published in: Nature (London) Vol. 465; no. 7294; pp. 91 - 95
• Main Authors: Cameron, Peter, Hiroi, Makoto, Ngai, John, Scott, Kristin
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 06.05.2010
• Subjects: Animals; Animals, Genetically Modified; Aqueous solutions; Behavior, Animal - physiology; Biochemistry. Physiology. Immunology; Biological and medical sciences; Cell Line; Drinking - physiology; Drosophila; Drosophila melanogaster - genetics; Drosophila melanogaster - metabolism; Drosophila melanogaster - physiology; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Epithelial Sodium Channels - genetics; Epithelial Sodium Channels - metabolism; Evacuations & rescues; Fundamental and applied biological sciences. Psychology; Gene expression; Gene mutations; Genetic aspects; Humans; In situ hybridization; Insecta; Invertebrates; Ion channels; Osmolar Concentration; Physiology. Development; Proteins; Sensory Receptor Cells - metabolism; Studies; Sucrose; Taste; Taste - physiology; Water; Water; Insecta; Drosophila; Osmoregulation; Ionic channel; Sensory receptor; Gene expression; Drosophilidae; Molecules; Neuron; Arthropoda; Water absorption; Invertebrata; Detection; Diptera
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature09011

The detection of water and the regulation of water intake are essential for animals to maintain proper osmotic homeostasis1. Drosophila and other insects have gustatory sensory neurons that mediate the recognition of external water sources2, 3, 4, but little is known about the underlying molecular mechanism for water taste detection. Here we identify a member of the degenerin/epithelial sodium channel family5, PPK28, as an osmosensitive ion channel that mediates the cellular and behavioural response to water. We use molecular, cellular, calcium imaging and electrophysiological approaches to show that ppk28 is expressed in water-sensing neurons, and that loss of ppk28 abolishes water sensitivity. Moreover, ectopic expression of ppk28 confers water sensitivity to bitter-sensing gustatory neurons in the fly and sensitivity to hypo-osmotic solutions when expressed in heterologous cells. These studies link an osmosensitive ion channel to water taste detection and drinking behaviour, providing the framework for examining the molecular basis for water detection in other animals.