A KSHV protein called latency-associated nuclear antigen, LANA for short, helps the virus hide out from the immune system in infected cells. When LANA takes the place of other proteins that control cell growth, it can cause uncontrolled cell replication.
The findings appear in a recent issue of the Proceedings of the National Academy of Sciences.
“This is the first report of LANA interfering with the crucial cellular protein called intracellular Notch,” says lead author Erle Robertson, PhD, Professor of Microbiology and the Program Leader of Tumor Virology at Penn’s Abramson Cancer Center. Notch is a signaling molecule that triggers cell development and maintains the stability of cells in many organs, such as the brain, heart, blood, and muscle.
“Intracellular notch, or ICN, promotes cell growth and proliferation, therefore it must be regulated so that these processes do not lead to cancer,” says Robertson. “We found that regulation of ICN through binding to another protein called Sel10, a cell-cycle regulatory protein, is derailed. The large complex of ICN, Sel10, and other factors is marked for degradation by a process called ubiquitination,” says Robertson. In normal uninfected cells, the level of ICN, and thus cell growth and proliferation, is fine-tuned by regulating ICN degradation.
LANA interferes with the degradation of ICN because it competes with ICN for the same binding site on Sel10. If LANA sits on Sel10, ICN cannot be degraded and cell growth and proliferation are no longer controlled. Kaposi’s sarcoma and primary effusion lymphoma are two of the viral-associated cancers that are common in immune-compromised patients.
This is the second mechanism discovered by Robertson and his associates by which KSHV subverts control of normal cell growth. Robertson’s group previously found that LANA marks tumor suppressors, such as p53 and VHL, for degradation.
Other herpes viruses, such as the one that causes cold sores and Epstein-Barr virus, which causes mononucleosis, are able to hide out in cells as well. “Whether these latent herpes viruses use some of the same strategies that we have found for LANA in KSHV has not been determined,” says Robertson.
This new role for LANA was discovered using specific human cell lines. The next step is to test whether LANA works the same way in animals infected with KSHV. “We have completed some studies in mice that indicate that LANA can contribute to tumor development in an animal in ways similar to what we have observed in cell culture,” says Robertson. The animal models will be useful for testing new drug therapies that may inhibit the activity of LANA and eventually prevent the growth of viral-associated cancers.
This work was funded by the National Institutes of Health and the Leukemia and Lymphoma Society of America. Co-authors are Ke Lan of Penn and the Chinese Academy of Science, and S.C. Verma, M. Marakami, B. Bajaj and R. Kaul, all from Penn.
Karen Kreeger | EurekAlert!
A novel synthetic antibody enables conditional “protein knockdown” in vertebrates
20.08.2018 | Technische Universität Dresden
Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover
There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.
The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
20.08.2018 | Information Technology
20.08.2018 | Life Sciences
20.08.2018 | Information Technology