By: Corey Buhay
Before she goes to sleep, my grandmother can decide what time she wants to wake up in the morning, down to the minute. 4:37 a.m.? 9:12 a.m.? She can do it. This always struck me as an instance of that same grandmotherly magic she uses to predict exactly when I would most desire homemade biscuits with honey.
Like many things in this world, her occult powers of timely wakening turn out not to be magic, but science. What’s more, this biological timekeeping, called your circadian rhythm, doesn’t only take place in some dusty back room of the brain tasked with keeping all those gears in motion. (That dusty backroom is called the hypothalamus, the region of the brain in charge of keeping the body’s master clock going.)
Timekeeping occurs in every cell, keeping them all humming together on the same timetable.
In a press release, UNC’s very own Dr. Aziz Sancar said his lab has known for a while that there are four proteins responsible for each cell’s clock. It’s only recently that the lab discovered just how they all work together. The lab just published a paper in Genes and Development about the interactions of these proteins.
There are four main actors in this 24-hour play. They are Period, BMAL1, Cryptochrome, and (aptly named) CLOCK. Period and Cryptochrome are buddies and so are BMAL1 and CLOCK.
The first dynamic duo, CLOCK and BMAL1, work together to turn on Cryptochrome and Period. Cryptochrome and Period start working, churning out other proteins. Some of these new proteins turn off CLOCK and BMAL1, which is pretty handy since it allows the rhythm to have a definite start and end point. Cryptochrome and Period are now awake, moving around the cell, doing their thing.
This is where the drama starts.
Sancar’s lab discovered that Cryptochrome and Period don’t do the same thing. In fact, the whole time Cryptochrome is working, minding its own business, Period is actually degrading it.
Sancar’s lab added and subtracted the four proteins from a cell to see what that cell would do with various combinations of the proteins. They discovered that without Period, Cryptochrome doesn’t break down. Period is important for wearing down Cryptochrome over a 24-hour period so that at the end of the period, the whole process can restart.
So that’s how my grandma does it. Or, how every cell of my grandma does it.
As for the biscuits, that’s a magic all of her own.