Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Channeling into cell control

23.01.2012
A new model of intracellular signaling via calcium ions will assist in understanding the effects of calcium fluctuations

A research team from the RIKEN Brain Science Institute in Wako has visualized and accurately modeled the molecular changes that open and close the internal membrane channels for calcium ions within cells1. The ions moving through these channels act as intracellular messengers, relaying information that regulates the activity of the proteins that control many critical processes of life and death—from fertilization through to development, metabolism and, ultimately, death.


Figure 1: A cell emitting fluorescent signals as a result of attaching specialized proteins to two of its channel-forming IP3Rs (scale bar, 10 µm). Copyright : PNAS

Previous work by the team showed that inositol trisphosphate (IP3) and calcium ions are involved in regulating channel opening and closing. The channels are formed from complexes of four IP3 receptors (IP3R) that bind IP3 and calcium. At low concentrations of calcium ions, channel opening is stimulated; but at higher levels, it is inhibited. Although cell biologists have proposed models depicting this process, they had failed to collect any definitive evidence supporting a particular the mechanism, until now.

In live cells, Takayuki Michikawa, Katsuhiko Mikoshiba and their colleagues attached fluorescent proteins to two of the channel-forming IP3Rs because these receptors change shape in response to the binding of IP3 and calcium, and energy flows between this pair of proteins in a process known as Förster resonance energy transfer (FRET) (Fig. 1). In a detectable way, FRET changes the fluorescent light emitted, so the impact of such links on the conformation of the channel can be studied.

The researchers found there were at least five binding sites on each IP3R, one for IP3 and at least four for calcium. Binding IP3 tended to bring the receptors forming the channel closer together, while calcium tended to make them relax. But the effects of combining the two were not simply additive. At a constant level of IP3, they observed an optimum concentration of calcium that had the most impact on opening the channel.

From these results, the researchers proposed a model whereby IP3 and calcium ions compete with one another—the binding of IP3 prevents calcium linking to certain sites, and vice versa. High concentrations of calcium prevent IP3 from binding at all. Further, the researchers proposed two different types of calcium binding sites: low-affinity sites responsible for channel activation, and high-affinity sites for inactivation.

“During the past five years, we have succeeded in visualizing IP3 dynamics and calcium pump activity,” Michikawa and Mikoshiba say. “In combination with the model for the calcium release channel described in this study, we are now ready to understand what happens in living cells during calcium ion oscillations.”

The corresponding author for this highlight is based at the Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute

gro-pr | Research asia research news
Further information:
http://www.riken.jp
http://www.researchsea.com

More articles from Life Sciences:

nachricht Hunting pathogens at full force
22.03.2017 | Helmholtz-Zentrum für Infektionsforschung

nachricht A 155 carat diamond with 92 mm diameter
22.03.2017 | Universität Augsburg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Pulverizing electronic waste is green, clean -- and cold

22.03.2017 | Materials Sciences

Astronomers hazard a ride in a 'drifting carousel' to understand pulsating stars

22.03.2017 | Physics and Astronomy

New gel-like coating beefs up the performance of lithium-sulfur batteries

22.03.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>