Brain protein tags track sleep and forecast wakefulness

A mouse study cited by Nature reports that protein tagging linked to protein kinase A creates a real-time clock for sleep: tagging declines during sleep and spikes with brief awakenings, tallying sleep duration and interruptions and predicting the likelihood of waking. If validated, this molecular signal could become a biomarker for sleep debt and help gauge alertness in high‑stakes jobs, but the work is a bioRxiv preprint and not yet peer‑reviewed. Some experts caution it may reflect vigilance or REM transition rather than sleep need, and follow-up experiments aim to test whether manipulating PKA could relieve sleep debt.