專題：Nature系列
動物必須能夠在它們環境中找到水才能生存，但它們是怎樣做到這一點的卻仍不清楚。現在，作為退化蛋白/上皮鈉通道家族中一員的PPK28，被發現是果蠅的水味道受體。
這個家族的其他蛋白已經被發現與機械刺激和鹽刺激的檢測有關。（生物谷Bioon.com）
生物谷推薦原文出處：
Nature doi:10.1038/nature09011
The molecular basis for water taste in Drosophila
Peter Cameron1, Makoto Hiroi1, John Ngai2 & Kristin Scott1,3
1Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, 16 Barker Hall,
2Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute and Functional Genomics Laboratory, 142 Life Sciences Addition,
3Howard Hughes Medical Institute, University of California-Berkeley, Berkeley, California 94720, USA
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.