Paradoxically, its manufacture involves two other proteins — including one linked to mental retardation — that typically prevent proteins from being made.
Previous research already established that long-term memory formation depends on Arc protein, but scientists did not know the mechanism that turned on this process.
To find it, they surveyed proteins in mouse brains that change or are activated after a nerve is stimulated and identified eEF2K (short for eukaryotic elongation factor 2 kinase) as a player. When turned on, eEF2K inhibits an important step of protein translation.
“This seemed strange, because it suggested that nerve cells might make Arc protein by using pathways typically thought to turn off protein manufacture,” says Paul Worley, M.D., a professor of neuroscience in the Johns Hopkins University School of Medicine.
Further examination of mouse brain slices lacking eEF2K in their nerve cells showed that when stimulated, such cells fail to make the usual pools of Arc protein, demonstrating that eEF2K is required for making Arc.
What it didn’t tell them was whether eEF2K specifically was responsible, or whether some other pathway is also involved, so researchers next treated the brain slices from normal mice with a chemical that inhibits protein manufacture by the same mechanism as eEF2K. At the same time that general protein synthesis was turned down, Arc translation actually increased, making it clear eEF2K, through its ability to turn down protein manufacture, somehow enabled a nerve cell to make Arc in response to nerve stimulation.
Meanwhile, Worley’s team proceeded to build on research showing that a protein linked to a form of mental retardation passed on by an abnormal “fragile X” chromosome also represses the manufacture of some proteins. The researchers looked at Arc protein levels in nerve cells lacking the fragile X mental retardation protein and found stable levels of Arc protein all the time, before, during, after and even without stimulation of the nerve cells. They concluded that without fragile X protein, the presumed “brakes” on the system, the manufacture of Arc goes unregulated.
“It’s sort of a seesaw relationship,” Worley says. When nerve cells are stimulated, eEF2K is activated to suppress protein manufacture generally, thereby allowing for the rapid manufacture of Arc, and, at the same time, fragile X mental retardation protein is stimulated to let Arc protein get made.
“By defining a mechanism that is associated with fragile X syndrome — the most common inherited cause of mental retardation and autism — it may help others to identify potential therapeutic targets to help with the disease,” Worley says.
The research was funded by the National Institute of Mental Health, the National Institute on Drug Abuse, and the National Institute on Aging.
Authors on the paper are Sunjin Park, Joo Min Park, Sangmok Kim, Jin-Ah Kim, Jason D. Shepherd, Constance L. Smith-Hicks, Shoaib Chowdhury, Walter Kaufmann, Dietmar Kuhl, Alexey G. Ryazanov, Richard L. Huganir, David J. Linden, and Worley, all of Hopkins.
Maryalice Yakutchik | Newswise Science News
New catalyst controls activation of a carbon-hydrogen bond
21.11.2017 | Emory Health Sciences
The main switch
21.11.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
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
21.11.2017 | Physics and Astronomy
21.11.2017 | Physics and Astronomy
21.11.2017 | Life Sciences