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 How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>