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 Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory

nachricht How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>