Featured Research

from universities, journals, and other organizations

Gatekeeping: Penn Researchers Find New Way To Open Ion Channels In Cell Membranes

Date:
July 17, 2006
Source:
University of Pennsylvania School of Medicine
Summary:
Researchers at the University of Pennsylvania School of Medicine have discovered a new way to open ion channels, in the membrane of cells. They found that an enzyme splits a lipid 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. The finding lays the conceptual groundwork for designing new drugs to control ion-channel activity.

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.

This work was supported by a research grant from the National Institutes of Health.


Story Source:

The above story is based on materials provided by University of Pennsylvania School of Medicine. Note: Materials may be edited for content and length.


Cite This Page:

University of Pennsylvania School of Medicine. "Gatekeeping: Penn Researchers Find New Way To Open Ion Channels In Cell Membranes." ScienceDaily. ScienceDaily, 17 July 2006. <www.sciencedaily.com/releases/2006/07/060717221858.htm>.
University of Pennsylvania School of Medicine. (2006, July 17). Gatekeeping: Penn Researchers Find New Way To Open Ion Channels In Cell Membranes. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2006/07/060717221858.htm
University of Pennsylvania School of Medicine. "Gatekeeping: Penn Researchers Find New Way To Open Ion Channels In Cell Membranes." ScienceDaily. www.sciencedaily.com/releases/2006/07/060717221858.htm (accessed October 22, 2014).

Share This



More Matter & Energy News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Thanks, Marty McFly! Hoverboards Could Be Coming In 2015

Thanks, Marty McFly! Hoverboards Could Be Coming In 2015

Newsy (Oct. 21, 2014) If you've ever watched "Back to the Future Part II" and wanted to get your hands on a hoverboard, well, you might soon be in luck. Video provided by Newsy
Powered by NewsLook.com
Robots to Fly Planes Where Humans Can't

Robots to Fly Planes Where Humans Can't

Reuters - Innovations Video Online (Oct. 21, 2014) Researchers in South Korea are developing a robotic pilot that could potentially replace humans in the cockpit. Unlike drones and autopilot programs which are configured for specific aircraft, the robots' humanoid design will allow it to fly any type of plane with no additional sensors. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Graphene Paint Offers Rust-Free Future

Graphene Paint Offers Rust-Free Future

Reuters - Innovations Video Online (Oct. 21, 2014) British scientists have developed a prototype graphene paint that can make coatings which are resistant to liquids, gases, and chemicals. The team says the paint could have a variety of uses, from stopping ships rusting to keeping food fresher for longer. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
China Airlines Swanky New Plane

China Airlines Swanky New Plane

Buzz60 (Oct. 21, 2014) China Airlines debuted their new Boeing 777, and it's more like a swanky hotel bar than an airplane. Enjoy high-tea, a coffee bar, and a full service bar with cocktails and spirits, and lie-flat in your reclining seats. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins