Biochemistry of sleep need

We feel sleepy when we have insufficient sleep. Also, we can recover from sleep deprivation only by taking sleep. What is sleep need? What is sleep debt? Actually, we cannot answer this simple question. Here, we investigated how brain proteins alter in Sik3-mutnat mice and sleep-deprived mice: both mice get very sleepy. We identified 80 proteins that show phosphorylation changes correlated with the amount of sleep need. We believe that we get a step closer to elucidating the molecular substrates of sleep need.