Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Research Technique Provides Clues into Cell Growth: Findings May Help Scientists Understand Tumor Spread

22.01.2004


Researchers at Washington University School of Medicine in St. Louis have developed a new probe that allows them to watch protein activity in living cells. In their initial study, which focused on a protein tentatively linked to the spread of cancerous cells, the team both proved their new technique works and revealed surprising new details about the protein’s activity.



The protein in this study, neuronal Wiskott–Aldrich syndrome protein (N-WASP), is naturally found in every cell in the body and is known to be involved in a wide range of cellular processes. One of its key functions is believed to be guiding cellular growth and movement within the body, including when tumor cells metastasize, or spread, from one organ to another.

“To our knowledge this is the first probe of its kind that allows us to actually see in a living system where, when and how proteins are activated,” says first author Michael E. Ward, a graduate student in anatomy and neurobiology. “This is significant progress in moving from examining the biochemistry of ground up cells to being able to study it in an intact cell.”


The study was led by Yi Rao, Ph.D., associate professor of anatomy and neurobiology. It appears online in the early edition of the Proceedings of the National Academy of Sciences and will be featured on the cover of the Jan. 27 print edition of the journal.
To design this new probe, the team took advantage of the fact that N-WASP folds in half when it is inactivated. They latched two fluorescent proteins onto the opposing ends of N-WASP — one yellow and one cyan (greenish-blue).

When stimulated by a particular wavelength of light, fluorescent proteins normally release energy in the form of light. In the case of yellow and cyan proteins, the light emitted appears either yellow or cyan. Under certain circumstances, light energy from the cyan protein can be transferred to the yellow protein since cyan is a higher energy light than yellow and energy naturally jumps from high- to low-energy states. The team hypothesized that, as N-WASP becomes activated and folds, the two ends would be brought closer together, resulting in an increase in the brightness of the yellow protein and a decrease in the brightness of the cyan protein. This phenomenon is called fluorescence resonance energy transfer.

While this phenomenon has been used previously to examine the activity of proteins other than N-WASP, this is the first study in which the natural folding and unfolding of a single protein was observed. All former efforts relied on artificially tethering two separate proteins together, which can produce deceptive results.

As they had hoped, the ratio of cyan to yellow light did accurately reflect N-WASP activity. Normally, N-WASP, so named because it belongs to a family of proteins implicated in the rare genetic disorder Wiskott-Aldrich syndrome, is only marginally activated by one of two proteins, PIP2 and CDC42. However, it becomes highly activated when simultaneously stimulated by the two proteins. In accordance with this synergistic effect, activation with only one of these proteins resulted in only a modest decrease in cyan light and increase in yellow light, while simultaneous activation with both resulted in a much more dramatic effect.

“It was exciting to discover that we could not only visualize N-WASP activation but also could visualize the specific integration of PIP2 and CDC42 stimulation,” Ward says. “This supports the idea that our probe is sensitive to normal cellular signaling processes.”

Using their new technique, the team recorded preliminary observations of N-WASP activation throughout living cells placed in a petri dish.

Traditionally, N-WASP was thought to be significantly active in filopodia, thin filaments that protrude from cells to help navigate through the body. As expected, N-WASP activity was high in these compartments.

However, several of the team’s other observations surprised them.

First, N-WASP and its stimulator proteins CDC42 and PIP2 all were active in “ruffles,” animated ridges on the cell membrane that also help cells move forward. According to Ward, research on N-WASP has never highlighted its potential role in ruffling.

Second, some of the highest levels of N-WASP activity were in the nucleus, despite the general assumption that the protein’s main functions are in cell movement, which occurs in the periphery of the cell.

“Because we were able to visualize where N-WASP is activated, we were able to show it’s activated in certain unexpected cellular compartments,” Ward says. “Now that we’ve demonstrated this technique is effective, we hope to further examine this protein’s activity and also to see whether similar probes can help us visualize other folding proteins.”


Ward ME, Wu JY, Rao Y. Visualization of spatially and temporally regulated N-WASP activity during cytoskeletal reorganization in living cells. Proceedings of the National Academy of Sciences, Jan. 27, 2004.

Funding from the National Institutes of Health, the Society for Progressive Supranuclear Palsy, the National Brain Tumor Foundation, the Muscular Dystrophy Association and the Leukemia Society of America supported this research.

Gila Z. Reckess | WUSTL
Further information:
http://aladdin.wustl.edu/medadmin/PAnews.nsf/news/2DA888C74CBB9BF686256E22006553A9?OpenDocument

More articles from Life Sciences:

nachricht Show me your leaves - Health check for urban trees
12.12.2017 | Gesellschaft für Ökologie e.V.

nachricht Liver Cancer: Lipid Synthesis Promotes Tumor Formation
12.12.2017 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Multi-year submarine-canyon study challenges textbook theories about turbidity currents

12.12.2017 | Earth Sciences

Electromagnetic water cloak eliminates drag and wake

12.12.2017 | Power and Electrical Engineering

Liver Cancer: Lipid Synthesis Promotes Tumor Formation

12.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>