In the fruitfly Drosophila scientists have discovered a new protein that is involved in the homeostatic regulation of sleep.
Amita Sehgal, PhD, professor of Neuroscience at the Perelman School of Medicine, University of Pennsylvania and her team conducted a screen of mutant flies to identify short-sleeping individuals and found one, which they dubbed redeye.
These mutants show a severe reduction in the amount of time they slumber, sleeping only half as long as normal flies. While the redeye mutants were able to fall asleep, they would wake again in only a few minutes.
The team found that the redeye gene encodes a subunit of the nicotinic acetylcholine receptor. This type of acetylcholine receptor consists of multiple protein subunits, which form an ion channel in the cell membrane, and, as the name implies, also binds to nicotine.
Although acetylcholine signaling-and cigarette smoking-typically promote wakefulness.
Levels of the redeye protein in the fly oscillate with the cycles of light and dark and peak at times of daily sleep. Normally, the redeye protein is expressed at times of increasing sleep need in the fly, right around the afternoon siesta and at the time of night-time sleep.
From this, the team concluded that the redeye protein promotes sleep and is a marker for sleepiness - suggesting that redeye signals an acute need for sleep, and then helps to maintain sleep once it is underway.
The study has been published in journal eLIFE.