Featured Research

from universities, journals, and other organizations

Plague Agent Helps Researchers Find Novel Signaling System In Cells

Date:
May 26, 2006
Source:
UT Southwestern Medical Center
Summary:
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.

Dr. Kim Orth (right), assistant professor of molecular biology, led a research team that included Sohini Mukherjee (left), student research assistant in molecular biology, and Gladys Keitany, research assistant in molecular biology, in discovering a regulatory mechanism that inhibits the immune system.
Credit: Image courtesy of UT Southwestern Medical Center

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.

Three species of 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.


Story Source:

The above story is based on materials provided by UT Southwestern Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

UT Southwestern Medical Center. "Plague Agent Helps Researchers Find Novel Signaling System In Cells." ScienceDaily. ScienceDaily, 26 May 2006. <www.sciencedaily.com/releases/2006/05/060526084014.htm>.
UT Southwestern Medical Center. (2006, May 26). Plague Agent Helps Researchers Find Novel Signaling System In Cells. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/2006/05/060526084014.htm
UT Southwestern Medical Center. "Plague Agent Helps Researchers Find Novel Signaling System In Cells." ScienceDaily. www.sciencedaily.com/releases/2006/05/060526084014.htm (accessed September 18, 2014).

Share This



More Health & Medicine News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Cost of Ebola

The Cost of Ebola

Reuters - Business Video Online (Sep. 18, 2014) As Sierra Leone prepares for a three-day "lockdown" in its latest bid to stem the spread of Ebola, Ciara Lee looks at the financial implications of fighting the largest ever outbreak of the disease. Video provided by Reuters
Powered by NewsLook.com
What HealthKit Bug Means For Your iOS Fitness Apps

What HealthKit Bug Means For Your iOS Fitness Apps

Newsy (Sep. 18, 2014) Apple has delayed the launch of the HealthKit app platform, citing a bug. Video provided by Newsy
Powered by NewsLook.com
Residents Vaccinated as Haiti Fights Cholera Epidemic

Residents Vaccinated as Haiti Fights Cholera Epidemic

AFP (Sep. 18, 2014) Haitians receive the second dose of the vaccine against cholera as part of the UN's vaccination campaign. Duration: 00:34 Video provided by AFP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins