Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New dye directly reveals activated proteins in living cells

13.09.2004


A series of experiments reported on this week in the journal Science shows for the first time that novel biosensor dyes can directly reveal activation of proteins in individual living cells.



The research, led by Dr. Klaus M. Hahn, professor of pharmacology at the University of North Carolina at Chapel Hill’s School of Medicine, demonstrated that at least one of the dyes Hahn developed makes it possible to dramatically visualize the changing activation and intracellular location of the protein Cdc42.

The novel dyes open new possibilities for screening the molecular effects of drugs within the living cell. Currently, automated "high throughput" drug assays are conducted on thousands of cells at a time, but in vitro, in laboratory test tubes. Cdc42, a member of the Rho family of proteins, regulates multiple and sometimes opposite functions within the cell: movement, proliferation, cell death and shape.


Injected into connective tissue cells, the dye "I-SO" displayed a bright green-colored fluorescence as Cdc42 activation and interaction with other proteins occurred. In addition, the dye proved highly sensitive, enabling detection of protein activation at low levels, unlike current fluorescence methods that require protein over-expression for detection. "For the first time we saw native Cdc42 activity in living cells," Hahn said. "But perhaps the most important aspect of the paper is that we demonstrated a new approach: We showed we can look at endogenous molecules and their activation using novel dyes."

Unlike other protein visualization methods, "you’re looking directly at the fluorescence from this dye, which means it’s much brighter and more sensitive," Hahn said. Also differing from current methods, the new approach does not require making modifications to the protein in question. "Many proteins occur in small amounts, so if you put in exogenous material you change everything," Hahn said.

Among the reasons Hahn and co-authors at Scripps Research Institute in La Jolla, Calif., decided to study the Rho proteins was that different members of the protein family each control a different aspect of cellular movement of extension and retraction. One family controls extension of the edge, another the formation of fibers, and still another controls tail retraction. "And the key to understanding this mechanism is to see where in time and space each of these is turned on and how it’s all coordinated," Hahn said. "So there’s a really good reason to look at this in live cells. You can’t understand spatio-temporal control if you look at this in a test tube."

Another reason to study Rho proteins is that their activation is necessary to induce essentially opposite behaviors. "They’re activated for proliferation and for cell death (apoptosis), also for motility. So it may be that this spatio-temporal control is what’s producing these differences."

Some of the study’s biological findings in that latter regard were tantalizing. Cdc42 induced formation of cell extensions called filopodia when it was activated around the filopodia base and not within the lengths, Hahn said. "When we looked at extension and retraction, we found that Cdc42 activation was remarkably correlated with both. It was activated at exact locations relative to cell extensions and was turned off in exact parallel with retraction."

Further experiments showed that this coordination was produced by "upstream signals" regulating both retraction and extension. "The use of fluorescent labeling of molecules in live cells was pioneered over a decade ago here at UNC," Hahn said. "My work with these new dyes is an extension of that work, it grew out of that."

L. H. Lang | EurekAlert!
Further information:
http://www.med.unc.edu

More articles from Life Sciences:

nachricht Complementing conventional antibiotics
24.05.2018 | Goethe-Universität Frankfurt am Main

nachricht Building a brain, cell by cell: Researchers make a mini neuron network (of two)
23.05.2018 | Institute of Industrial Science, The University of Tokyo

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

These could revolutionize the world

24.05.2018 | Materials Sciences

Nuclear physicists leap into quantum computing with first simulations of atomic nucleus

24.05.2018 | Physics and Astronomy

Electron tomography technique leads to 3-D reconstructions at the nanoscale

24.05.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>