动物必须能够在它们环境中找到水才能生存，但它们是怎样做到这一点的却仍不清楚。现在，作为退化蛋白/上皮钠通道家族中一员的PPK28，被发现是果蝇的水味道受体。
这个家族的其他蛋白已经被发现与机械刺激和盐刺激的检测有关。
生物谷推荐原文出处：
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.
