Researchers Identify Key Molecular Step to Fending Off Viruses
UT Southwestern Medical Center researchers have determined how a protein that normally latches onto molecules inside cells and marks them for destruction also gives life to the body’s immune response against viruses.
The researchers discovered that a certain form of the “death” protein ubiquitin interacts with another protein, called RIG-I, but does not mark it for destruction. Instead, this form of ubiquitin binds to and activates RIG-I, which is known to trigger the body’s immune system when a virus invades a cell.
Dr. Zhijian Chen, professor of molecular biology at UT Southwestern, is senior author of the study, which is available online and in the journal Cell.
Chen and his colleagues reconstituted key elements of the human innate immune system in laboratory test tubes and found ubiquitin forms a unique chain-like structure that associates with RIG-I before RIG-I can get to work fighting viruses. The innate immune system is the body’s first generic response against invading pathogens.
“Activation of RIG-I is the first line of our immune defenses against viral infections,” said Chen, an investigator for the Howard Hughes Medical Institute at UT Southwestern. “Understanding how it comes to life is a key step in developing new approaches to antiviral therapies. Having this test-tube system could help us identify substances that enhance the body’s antiviral immunity.”
Chen said his team’s experiments mark the first time innate immunity has been recapitulated in a test tube. The findings provide one of the missing pieces in the complex puzzle of how the body fights off infection, he added.
Chen is now focusing on how activated RIG-I interacts with another protein called MAVS, also essential for immune response.
Other UT Southwestern researchers involved in the study were Dr. Wenwen Zeng and Dr. Ming Xu, both postdoctoral researchers in molecular biology; Lijun Sun and Xiang Chen, both HHMI research scientists; Xiaomo Jiang, graduate student; Dr. Fajian Hou, instructor of molecular biology; and Dr. Anirban Adkikari, former postdoctoral researcher in molecular biology.
The study was funded by the National Institutes of Health and the Welch Foundation.
CDC Urges Vigilance: New Recommendations for Monitoring and Testing H5N1 Exposures
July 11th 2025With avian influenza A(H5N1) infections surfacing in both animals and humans, the CDC has issued updated guidance calling for aggressive monitoring and targeted testing to contain the virus and protect public health.
IP LifeLine: Layoffs and the Evolving Job Market Landscape for Infection Preventionists
July 11th 2025Infection preventionists, once hailed as indispensable during the pandemic, now face a sobering reality: budget pressures, hiring freezes, and layoffs are reshaping the field, leaving many IPs worried about their future and questioning their value within health care organizations.
A Helping Hand: Innovative Approaches to Expanding Hand Hygiene Programs in Acute Care Settings
July 9th 2025Who knew candy, UV lights, and a college kid in scrubs could double hand hygiene adherence? A Pennsylvania hospital’s creative shake-up of its infection prevention program shows that sometimes it takes more than soap to get hands clean—and keep them that way.
