New publications
Scientists have discovered a protein that regulates the biological clock
Last reviewed: 30.06.2025
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
A protein called QUASIMODO tells the internal biological clock the current time of day.
It is known that every living organism has a built-in biological clock that coordinates its biochemistry, physiology and behavior with the time of day. It is intuitively clear that this clock must somehow synchronize with the length of daylight hours, that is, rely on information perceived by visual receptors. Scientists from Queen Mary College, University of London, have managed to find a protein that tells our internal clock whether it is daytime or deep night outside.
Professor Ralph Staniewski and his team spent years studying the circadian rhythm regulation system; the fruit fly Drosophila served as a model object for the researchers. Previously, scientists discovered a special photoreceptor protein, cryptochrome, which works only with neurons belonging to the biological clock system. Analyzing the functioning of the cryptochrome receptor, the authors came to the conclusion that there must be another mechanism by which our internal clocks are checked against real time. Research in this direction led to the discovery of a protein called QUASIMODO (QSM).
It turned out that the synthesis of this protein significantly increases in response to light. QUASIMODO turned out to be associated with negative feedback with another protein of the circadian system - TIMELESS (TIM): an increase in the content of the first decreased the concentration of the second.
The report, published in the journal Current Biology, shows that the TIMELESS protein's oscillations reflect the time of day; it is this protein that tells fruit flies when it is time to sleep or, conversely, "to lead an active lifestyle." But the switch for TIMELESS itself is QUASIMODO, which reacts to light and is thus a "time standard": it is with its help that the insect brain distinguishes day from night.
While regular fruit flies fell into a “circadian arrhythmia” under constant illumination, their activity was maintained by QUASIMODO; fruit flies with the QSM gene switched off demonstrated cyclicity in the synthesis of the TIMELESS protein and corresponding behavior. According to the researchers, such a dual system of circadian rhythm regulation involving cryptochrome and QUASIMODO may exist not only in insects, but also in humans. If so, then it is QUASIMODO that helps us adjust to a new circadian rhythm when traveling between time zones.
[ 1 ]