Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Plague agent helps UT Southwestern researchers find novel signaling system in cells

29.05.2006
The bacterium that causes bubonic plague would seem unlikely to help medical scientists, but researchers at UT Southwestern Medical Center have harnessed it to uncover a new regulatory mechanism that inhibits the immune system.

the Yersinia bacteria, known to cause plague and gastroenteritis, contain a small molecule, called a virulence factor, that the researchers have found modifies host enzymes critical to normal functioning.

"This type of modification has never been seen in cells and presents a new paradigm for how cells may regulate signaling," said Dr. Kim Orth, assistant professor of molecular biology and senior author of the study appearing in the May 26 edition of Science.

"Yersinia is a nasty pathogen that uses an arsenal of virulence factors to cause disease," she said.

When a cell is infected with a bacterial pathogen, it activates a chain of reactions involving enzymes. One enzyme adds a group of atoms containing phosphorus — called a phosphate group — to another enzyme, a process called phosphorylation, which spurs that enzyme to add a phosphate group to yet another enzyme, and so on. These "cascading" events trigger an appropriate immune response.

Yersinia, however, has the ability to prevent its host from mounting the response, enabling the bacteria to survive and multiply.

The researchers found that one of the Yersinia outer proteins, called YopJ, cripples these cascades by adding a small molecule called an acetyl group to two key sites on a host enzyme where the phosphate groups are usually added.

Because the host’s enzymes are modified by acetyl groups, they can no longer be activated by phosphate groups, and the enzymatic cascade critical for triggering an innate immune response is not activated.

The internal signaling that YopJ affects is common to many species, from yeast to mammals. In addition, other pathogens that attack animals and plants use proteins that are similar to YopJ.

The research is not geared toward finding a cure for plague, which affects about a dozen people in the United States a year and is treatable with antibiotics. Instead, the scientists are working to find out how the pathogen disrupts the immune system and to understand the machinery critical for stimulating an immune response.

"There are many virulence factors used by bacterial pathogens to co-opt the host signaling molecules," Dr. Orth said. "These virulence factors affect central signaling machinery, and we want to understand how they are doing it."

Understanding the relationship between the pathogens and the hosts will help researchers uncover critical steps in how host cells normally operate, Dr. Orth said.

"The next step is to see whether the addition of acetyl groups to key sites on enzymes during cellular signaling is normal for animal and plant cells, and if so, under what circumstances," said Dr. Orth.

Other UT Southwestern researchers involved in the study were first author Sohini Mukherjee, student research assistant in molecular biology; Gladys Keitany, research assistant in molecular biology; Dr. Yan Li, instructor of biochemistry; Yong Wang, research assistant in molecular biology; Dr. Haydn Ball, assistant professor of biochemistry; and Dr. Elizabeth Goldsmith, professor of biochemistry.

The work was supported by the National Institute of Allergy and Infectious Diseases, the Beckman Foundation and the Welch Foundation.

Aline McKenzie | EurekAlert!
Further information:
http://www.utsouthwestern.edu

More articles from Life Sciences:

nachricht How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>