Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Think fast! Rice undergrad unlocks nerve speed secret

18.07.2006
Study finds protein responsible for quick release of neural signals

In the second it takes you to read these words, tens of thousands of vesicles in your optic nerves are released in sequence, opening tiny surface pores to pass chemical signals to the next cell down the line, telling your brain what you're seeing and your eyes where to move. Thanks to two new studies – including one spearheaded by an undergraduate biochemistry student at Rice University and published online today by Nature Structural and Molecular Biology – scientists have defined the function of a key protein that nerve cells use to pass information quickly.

Like all cells in our bodies, nerve cells are encased in a membrane, a thin layer of fatty tissue that walls off the outside world from the cell's interior. And like other cells, nerve cells use a complex system of proteins as sensors, switches and activators to scan the outside world and decide when to open membrane doorways to take in food, expel waste and export chemical products to the rest of the body.

Many studies suggest that a group of proteins called SNAREs act like the cell's loading dock managers, deciding when to open the door to release shipments of chemical freight. SNAREs form a docking bay for cartons of chemicals encased in their own fatty membranes.

"Nerve cells are one of the few cells in our bodies in which vesicles are prepositioned at the cell membrane, because they have to be ready to release neurotransmitter to the next nerve cell at a moment's notice," said principal researcher James McNew, assistant professor of biochemistry and cell biology.

SNAREs are a key player in membrane fusion. They oversee the merger of the cell's outer membrane with the membrane encasing the chemical freight, and they do it in such a way that the freight can be exported, but no outside cargo can enter.

"With nerve cells, we've known that SNAREs provide the mechanical energy for membrane fusion, and another protein called synaptotagmin is the actuator," McNew said. "We also knew there was a chemical brake in the system, something that held the pre-positioned vesicle in check, but poised for release. These new studies clearly show that the brake is a protein called complexin."

Rice's study, which was conducted in McNew's lab, largely by undergraduate Johanna Schaub, involved in vitro experiments on a synthetic and highly controlled complex of membranes and proteins. Via these experiments, Schaub was able to show that SNARE-driven membrane fusion – the act that opens the door for neurotransmitter to leave the neuronal cell – was inhibited by complexin.

"By halting fusion partway, complexin essentially shortens the response time for signal transmission," said Schaub, who will begin graduate school at Stanford University in the fall. "The nerve cell can almost instantaneously pass on its information."

McNew said the finding is independently confirmed by work published online June 22 by Science magazine. In that study, Columbia University's James Rothman and colleagues created mutant cells with SNAREs on the outside rather than the inside, and they used the cells to show that complexin could inhibit fusion that would otherwise be expected to proceed.

"Complexin is the brake," McNew said. "It says, 'Stop. Don't go any further until you get the signal from synaptotagmin.'"

Jade Boyd | EurekAlert!
Further information:
http://www.rice.edu

More articles from Life Sciences:

nachricht Seeing on the Quick: New Insights into Active Vision in the Brain
15.08.2018 | Eberhard Karls Universität Tübingen

nachricht New Approach to Treating Chronic Itch
15.08.2018 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

Unraveling the nature of 'whistlers' from space in the lab

15.08.2018 | Physics and Astronomy

Diving robots find Antarctic winter seas exhale surprising amounts of carbon dioxide

15.08.2018 | Earth Sciences

Early opaque universe linked to galaxy scarcity

15.08.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>