This study marks the first discovery of so-called “good” prion-like proteins in human cells and the first to find such proteins involved in innate immunity: the way the body recognizes and responds to threats from viruses or other external agents, said Dr. Zhijian “James” Chen, professor of molecular biology and senior author of the study in the Aug. 5 print edition of the journal Cell.
"An understanding of how cells maintain good prion-like proteins called MAVS [mitochondrial antiviral signaling] protein may help us understand how some prions turn bad,” said Dr. Chen, a Howard Hughes Medical Institute investigator at UT Southwestern. Moreover, the research may also deepen our knowledge of innate immunity and host defense, he said.
Prions are misfolded, self-perpetuating proteins responsible for fatal brain infections such as bovine spongiform encephalopathy – so-called mad cow disease – in cattle and the extremely rare variant Creutzfeldt-Jakob Disease (vCJD) in some people who eat beef from infected cattle. Currently all prion-related diseases are untreatable and are fatal.
The MAVS prion-like proteins usually are scattered on the membranes of the energy-producing organelles called the mitochondria that reside inside cells throughout the body, he explained.
UT Southwestern researchers, investigating the cellular response to invasion by a member of the family of viruses that includes influenza and hepatitis, discovered that the MAVS proteins change shape and recruit other MAVS proteins to misfold and aggregate [cluster] in tough clumps on the surface of the mitochondrial membranes to defend against viral assault, Dr. Chen said.
The researchers created a setup that mimicked the human immune response, but in a controlled laboratory environment where they were able to break open cells and study the cellular components. When those components were mixed with viral RNA (the genetic material also known as ribonucleic acid), the MAVS proteins still formed large clusters.
“Remarkably, the MAVS proteins behave like prions and effectively convert nearby proteins into aggregates on the mitochondrial membrane,” Dr. Chen said. He noted that the aggregates are necessary for the cells to churn out immunity-boosting interferon molecules. When the MAVS activity is blocked, the antiviral defense stops.
The MAVS’ prion-like mechanism gives no indication of the out-of-control replication seen in disease-causing prions, Dr. Chen said, providing an intriguing area for future research.
Other UT Southwestern researchers involved in the study were lead author Dr. Fajian Hou, instructor of molecular biology; Dr. Lijun Sun, assistant professor of molecular biology and an HHMI research specialist; Dr. Hui Zheng, postdoctoral fellow in cell biology; Brian Skaug, a student in the medical scientist training program; and Dr. Qui-Xing Jiang, assistant professor of cell biology.
The study was funded by grants from the National Institutes of Health and the Welch Foundation.This news release is available on our World Wide Web home page at
Deborah Wormser | Newswise Science News
Bacteria as pacemaker for the intestine
22.11.2017 | Christian-Albrechts-Universität zu Kiel
Researchers identify how bacterium survives in oxygen-poor environments
22.11.2017 | Columbia University
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
22.11.2017 | Business and Finance
22.11.2017 | Physics and Astronomy
22.11.2017 | Physics and Astronomy