Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research Reveals How Cells Tell Time

09.06.2009
The fuzzy pale mold that lines the glass tubes in Dr. Yi Liu’s lab doesn’t look much like a clock.
But this fungus has an internal, cell-based timekeeper nearly as sophisticated as a human’s, allowing UT Southwestern Medical Center physiologists to study easily the biochemistry and genetics of body clocks, or circadian rhythms.

In a new study appearing online this week in the Proceedings of the National Academy of Sciences, Dr. Liu and his co-workers have found that this mold, which uses a protein called FRQ as the main gear of its clock, marks time by a sequence of changes in the protein’s chemical structure.

Dr. Liu said the new finding might someday help researchers develop treatments for human sleep disorders and other problems associated with a faulty biological clock.

“This timekeeping protein is really the core component of the circadian clock,” said Dr. Liu, professor of physiology at UT Southwestern and senior author of the study.

Despite the evolutionary distance from mold to man, mechanisms controlling their circadian clocks are very similar. In both, circadian rhythms control many biological processes, including cell division, hormonal release, sleep/wake cycles, body temperature and brain activity.

The researchers employed a fungus called Neurospora, an organism frequently used in studies on genetics and cell processes, especially circadian rhythms. It reproduces in the dark and rests in the light.

A decade ago, Dr. Liu discovered that FRQ controlled the cellular clock in Neurospora by chemical changes of its protein structure. As the day goes on, the cell adds chemical bits called phosphates to the protein. Each new phosphate acts like a clock’s ticking, letting the cell know that more time has passed.

When the number of phosphates added to FRQ reaches a certain threshold, the cell breaks it down, ready to start the cycle again.

The researchers, however, did not know where the phosphates attached to FRQ, how many got added throughout a day, or how they affected the protein’s ability to “tell” time.

In the current study, the researchers used purified FRQ to analyze the specific sites where phosphate groups attach. In all, the researchers found 76 phosphate docking sites.

“This is an extremely high number,” Dr. Liu said. “Most proteins are controlled by only a handful of phosphate sites.”

They also studied how these phosphates are added to FRQ daily and found that two enzymes are responsible for adding most of the phosphate groups in Neurospora. They also found that the total number of phosphates oscillates robustly day by day.

In addition, the researchers created a series of mutations in many of the phosphate docking sites, creating strains of mold that had abnormally short or long daily clocks.

In upcoming studies, the researchers plan to identify which enzymes add phosphates to specific sites and exactly how changes in a particular site affect a cell’s clock.

Other UT Southwestern physiology researchers contributing to the work were co-lead authors Dr. Chi-Tai Tang, postdoctoral researcher, and Dr. Shaojie Li, former postdoctoral researcher; Dr. Joonseok Cha, postdoctoral fellow; Dr. Guocun Huang, assistant instructor; and Dr. Lily Li, former postdoctoral researcher. Researchers from the National Institute of Biological Sciences in China and the Chinese Academy of Sciences also participated.

The study was supported by the National Institutes of Health and the Welch Foundation.

Visit www.utsouthwestern.org/sleep to learn more about UT Southwestern’s clinical services in sleep and breathing disorders.

Dr. Yi Liu -- http://www.utsouthwestern.edu/findfac/professional/0,2356,42920,00.html

Aline McKenzie | Newswise Science News
Further information:
http://www.utsouthwestern.edu

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
21.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Nagoya physicists resolve long-standing mystery of structure-less transition

21.08.2017 | Materials Sciences

Chronic stress induces fatal organ dysfunctions via a new neural circuit

21.08.2017 | Health and Medicine

Scientists from the MSU studied new liquid-crystalline photochrom

21.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>