Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Like Eavesdropping at a Party

01.08.2008
Scientists Discover How a Tiny Protein Senses All the Communications in a Cell

Cells rely on calcium as a universal means of communication. For example, a sudden rush of calcium can trigger nerve cells to convey thoughts in the brain or cause a heart cell to beat.

A longstanding mystery has been how cells and molecules manage to appropriately sense and respond to the variety of calcium fluctuations within cells.

Reporting in the June 27 issue of Cell, a team of biomedical engineers at the Johns Hopkins School of Medicine has discovered how the calcium sensor protein calmodulin can gauge both the local flow of calcium, in through the closest channel, as well as the global calcium flow entering the many channels across the entire cell.

... more about:
»Cell »Yue »calmodulin »lobe

“It’s like being at a cocktail party where the easiest person to listen to is the one closest to you, but we all have the ability to keep an ear out for other interesting conversations going on throughout the room,” says David Yue, M.D., Ph.D., a professor of biomedical engineering at Hopkins. “It turns out that calmodulin is doing a similar thing, sensing the calcium coming through the closest channel through one ear while the other ear ‘listens’ to the calcium coming through distant channels across the cell.”

Normally, calmodulin is positioned right near each calcium channel. Several years ago, scientists discovered that calmodulin somehow can switch its sensory focus between local calcium and global calcium entering the cell through channels at a distance.

The calmodulin protein, explains Yue, is made of two ball-like lobes, and it’s these two lobes that act as the different calcium-sensing “ears.” The C lobe listens locally and the N lobe listens globally, across the whole cell. To figure out how calmodulin’s two lobes can sense different sources of calcium, the team took a two-pronged approach.

First, they used computers to perform mathematical simulations that tested different potential calcium detection mechanisms of the calmodulin lobes. Others have shown that the C lobe of calmodulin hangs onto calcium for a long time, whereas the N lobe lets go rapidly. Their simulations suggested that these slight differences in calcium holding time might play a role in calmodulin’s ability to sense both local and global calcium levels. “Once a local calcium ion sticks to the C lobe, it seldom lets go, and so the local calcium dominates,” says Yue.

By contrast, the N lobe would rapidly let go of calcium and then be empty and available to bind calcium entering the cell from distant calcium channels, allowing reception of global calcium. Similar to the cocktail party, it’s easiest to catch other conversations during the pauses in your own conversation.

The research team then verified their mathematical predictions by testing real calmodulin proteins attached to calcium channels. Using a new approach, they precisely controlled calcium pulses through single calcium channels and watched how calmodulin responded. They were able to confirm the mathematical models.

Understanding the language of calcium is critical for understanding how cells communicate, says Yue, and also important for understanding neural diseases. For instance, early antipsychotic drugs may work by blocking calmodulin action. “Now that we are learning how these drugs actually work,” Yue says, “we can contribute our new understanding of calmodulin to the design of next-generation drugs with greater potency and fewer side effects.”

The research was funded by the National Institutes of Health.

Authors on the paper are Michael Tadross, Ivy Dick and Yue, all of Hopkins.

Audrey Huang | Newswise Science News
Further information:
http://www.jhmi.edu

Further reports about: Cell Yue calmodulin lobe

More articles from Life Sciences:

nachricht Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Global study of world's beaches shows threat to protected areas

19.07.2018 | Earth Sciences

New creepy, crawly search and rescue robot developed at Ben-Gurion U

19.07.2018 | Power and Electrical Engineering

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>