Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Together, biological membranes prevail

30.01.2007
Researchers at the University of Illinois at Urbana-Champaign have developed a novel method to visualize the fusion of biological membranes at the single-event resolution

Observing the individual fusion events revealed an unprecedented detailed picture of membrane fusion, which was chronicled in one of the cover stories in the December 2006 issue of the journal Proceedings of National Academy of Sciences (PNAS).

"Undoubtedly, understanding the mechanisms of this basic life phenomenon is of great biological interest, and there have been extensive studies at the theoretical and experimental level to this end," stated Taekjip Ha, a professor of physics at Illinois and a Howard Hughes Medical Institute investigator. "Previous studies suggested various physical intermediates for the membrane fusion, but the limitations of the approaches at hand did not allow a solid consensus to be reached."

Compartmentalization in cells is achieved by lipid membranes. Membrane fusion is an elementary biological event which comes in various forms. From cellular trafficking to neuro-transmitter release, merging of two membranes is essential for carrying out vital processes of life. This important task is executed by membrane proteins called SNAREs. Complementary SNARE proteins residing within the incoming and target membranes form a bundle, and bring the two membranes close enough for the merging to occur. The fusion is thought to proceed through highly fleeting intermediates that are very difficult to study when many membrane fusion events are averaged over as has been done in most of previous studies.

Alternatively, the Illinois team, led by Ha, developed an elegant method which used fluorescence resonance energy transfer (FRET) technique to detect SNARE mediated membrane fusion. In FRET, a pair of green and red dyes is used where only the green dye can directly be excited by a laser. The red dye lights up if some of the energy from the green dye hops over to the red dye which becomes increasingly efficient at short distances. Their team prepared two different batches of SNARE-decorated vesicles, one with the green dyes and the other red dyes, and observed them using highly sensitive fluorescence microscopy.

The vesicles with the red dyes were then specifically immobilized on a polymer-passivated glass surface. The polymer coating acted as a cushion and prevented the non-specific binding of vesicles on the surface. As the green labeled vesicles were injected into the flow chamber, the vesicles could fuse upon SNARE-SNARE interaction. The merging of the two membranes result in mixing of the dyes and the level of mixing is reflected as changes in the FRET signal. Using this approach, the researchers could obtain real-time movies of fusion events single vesicles and uncovered various intermediates and pathways during the fusion reaction. The different fates of liposomes subsequent to fusion were also dissected at the level of single-fusion events. The results of the study was highlighted by a commentary in the same issue of the journal PNAS and by a "News and Views" article in the January issue of Nature Structural and Molecular Biology.

The new single-vesicle approach to study membrane fusion, developed by postdoctoral associate Tae-Young Yoon and graduate student Burak Okumus, opens not only a new avenue for the SNARE field, but also provides a native-like environment for the single molecule studies of membrane proteins which would fill a gap in the researchers' toolkit. The work was done in collaboration with Fan Zhang and Professor Yeon-Kyun Shin of Iowa State University and was funded by grants from the National Institute of General Medical Sciences. The research team is currently working on the neuronal SNAREs hoping to shed new light on the membrane fusion events essential for brain functioning.

Richard Kubetz | EurekAlert!
Further information:
http://www.uiuc.edu

More articles from Medical Engineering:

nachricht Virtual Reality in Medicine: New Opportunities for Diagnostics and Surgical Planning
07.12.2016 | Universität Basel

nachricht 3-D printed kidney phantoms aid nuclear medicine dosing calibration
06.12.2016 | Society of Nuclear Medicine

All articles from Medical Engineering >>>

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 >>>