An international team of scientists has discovered what amounts to a molecular reset button for our internal body clock. Their find reveals a potential target to treat a range of disorders, from sleep disturbances to other behavioral, cognitive and metabolic abnormalities, commonly associated with jet lag, shift work and exposure to light at night, as well as with neuropsychiatric conditions such as depression and autism.
In a study published online in Nature Neuroscience, the authors — led by researchers at McGill and Concordia universities in Montreal — report that the body’s clock is reset when a phosphate combines with a key protein in the brain. This process, known as phosphorylation, is triggered by light. In effect, light stimulates the synthesis of specific proteins called Period proteins that play a pivotal role in clock resetting, thereby synchronizing the clock’s rhythm with daily environmental cycles.
Shedding light on circadian rhythms
“This study is the first to reveal a mechanism that explains how light regulates protein synthesis in the brain, and how this affects the function of the circadian clock,” says senior author Nahum Sonenberg, a professor in McGill’s Department of Biochemistry.
In order to study the brain clock’s mechanism, the researchers mutated the protein known as eIF4E in the brain of a lab mouse so that it could not be phosphorylated. Since all mammals have similar brain clocks, experiments with the mice give an idea of what would happen if the function of this protein were blocked in humans.