Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Protein key to trafficking in nerve terminals

23.07.2004


A protein characterized by researchers at Baylor College of Medicine plays an important role in communication between neurons. This protein is overactive (up-regulated) in children with Down’s Syndrome.



Identifying this protein - Dap160 — and its function is an important step in understanding how neurons communicate with one another, said Dr. Hugo Bellen, BCM professor of molecular and human genetics, a Howard Hughes Medical Institute investigator, and director of the program in developmental biology. The report appears in the July 22, 2004, issue of the journal Neuron.

Dap 160 was found as part of a new screen developed in Bellen’s laboratory. The screen revealed many genes involved in neuronal function and development, said Bellen. Dap160 stands for Dynamin-associated protein of 160 kD (kilodaltons). Dynamin is a protein that is crucial to the final portion of the synaptic process.


Neurotransmitters are the chemicals that contain the message to be transmitted when neurons talk to each other or to other cells. These chemicals are contained in small vesicles inside nerve endings called synapses.

When a nerve pulse invades the nerve ending, these vesicles fuse with the membrane at the tip of the nerve ending (called the synaptic membrane). At this point, vesicles release their contents so that a nearby cell receives the message.

"You need to retrieve the vesicles at the synapse to maintain a constant supply of vesicles in the nerve terminal," said Bellen. At least two distinct types of vesicle retrieval occur at the synapse, but the most well studied mechanism of vesicle retrieval is based on retrieving little pieces of membrane from the synaptic membrane. As the vesicles start to bud off the cell membrane, dynamin accumulates on the vesicle. The role of this protein is still controversial, Bellen said. Some people think it’s a "pinchase," pinching the vesicle off the cell membrane. Others think that it recruits other proteins to help pinching off the vesicle.

When Dap160, which binds dynamin, is removed from the vesicle retrieval process, the pinching-off either does not occur properly, or occurs too late. As a result, the vesicle keeps growing and subsequently becomes loaded with too much neurotransmitter. Bellen and his colleagues believe that Dap160 stabilizes the complex of molecules involved in the retrieval and formation of vesicles, allowing for neurotransmitters to be released in a continuous fashion.

"Besides budding from the membrane, there is at least one other form of vesicle retrieval at the synapse", Bellen said. A rapid retrieval mechanism called "kiss and run" occurs when the vesicle fuses with the membrane but the vesicle membrane does not collapse into the synaptic membrane. Rather, kiss and run vesicles release neurotransmitters through a pore in the membrane. The vesicles are then retrieved by pinching of the fusion pore at the site of release. These vesicles stay close to release sites and are reused immediately.

Interestingly, Dap160 is not only involved in retrieving vesicles from the membrane, but it is also implicated in kiss and run type vesicle recycling. This has important implications for the regulation of vesicle retrieval mechanisms at the synapse, Bellen said.

Ross Tomlin | EurekAlert!
Further information:
http://www.bcm.tmc.edu

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>