Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gatekeeping: Penn researchers find new way to open ion channels in cell membranes

19.07.2006
Implications for channel-related disorders, drug design

Using an enzyme found in the venom of the brown recluse spider, researchers at the University of Pennsylvania School of Medicine have discovered a new way to open molecular pores, called ion channels, in the membrane of cells. The research team – Zhe Lu, MD, PhD; Yajamana Ramu, PhD; and Yanping Xu, MD, PhD of the Department of Physiology at Penn – screened venoms from over 100 poisonous invertebrate species to make this discovery.

The enzyme, sphingomyelinase D (SMase D), splits a lipid called sphingomyelin that surrounds the channel embedded in the cell membrane. As a result, the channel opens to allow the passage of small ions into and out of the cell, thereby generating electrical currents.

The new study, published online earlier this month in the journal Nature, describes how SMase D opens one type of ion channel called a voltage-gated potassium channel (from brain, but experimentally expressed in the membrane of an oocyte, or egg cell) without changing the membrane voltage. The finding introduces a new paradigm for understanding the gating of ion channels and lays the conceptual groundwork for designing new drugs to control ion-channel activity in medical intervention.

Voltage-gated ion channels are embedded in the cell membranes of most types of cells. It has been known for over half a century that the channels open and close in response to changes in electric voltage across the cell membrane, hence their name. In some the cells, (commonly called "excitable"), such as nerve, muscle, heart, and hormone-secreting cells, the channels underlie electrical signaling. They selectively allow the passage of small ions such as sodium, potassium, or calcium into and out of the cell. The precisely controlled passage of ions generates the electrical currents that enable nerve impulse transmission, hormone secretion, and muscle contraction and relaxation. When there are changes to the channel, such as by mutations in a channel gene, disease can result. For example, mutations in some channel genes cause cardiac arrhythmias, including a form of the lethal long QT syndrome.

Voltage-gated ion channels are also present in the so-called non-excitable cells (such as immune, blood, and bone cells) whose membrane voltage stays largely constant, as opposed to the excitable cells whose membrane voltage constantly varies in a precisely controlled manner. How the activity of channels in non-excitable cells is regulated has been a long-standing biological mystery. This new finding that SMase D can open ion channels without changing membrane voltage provides a clue to the mystery.

Karen Kreeger | EurekAlert!
Further information:
http://www.uphs.upenn.edu/

More articles from Health and Medicine:

nachricht TSRI researchers develop new method to 'fingerprint' HIV
29.03.2017 | Scripps Research Institute

nachricht Periodic ventilation keeps more pollen out than tilted-open windows
29.03.2017 | Technische Universität München

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

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...

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

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>