Radio and cable are not required for communication within and between living cells. Rather, signal transduction in cells is performed by a multitude of proteins.
A protein with two functions: Using a clever trick, the CASK kinase compensates - at least in part - for its low activity. One part of the protein actively recruits neurexin proteins and places them in close proximity to the kinase. Wahl / MPIbpc
In order to transfer and interpret these signals correctly, activities of these proteins have to be precisely synchronized. Their subtle regulation is controlled by a sophisticated system, in which so called protein kinases play a key role. An international team of scientists from Dallas (USA), Göttingen and Hamburg (Germany) have now discovered a kinase, which seems superior under difficult conditions. Whereas all known kinases function only in the presence of magnesium, the pseudokinase CASK has found a trick to do away with this trace element.
The protein seems to be directly involved in formation of contact sites - synapses - during early development of the nervous system. Pseudokinases like CASK have so far been considered inactive. At least some of them seem to have been labelled "not useful" without good reason in the past. (Cell, April 18, 2008)
Human beings must permanently adjust to new situations in their environment and react in an appropriate manner. Likewise, living cells receive a large number of signals which they need to transfer and to interpret. Often, cells are stimulated to grow or to divide, to start a developmental process or to initiate an immune response. To do so, numerous actors within cells - the proteins - have to perform in a precisely coordinated manner. A complex control system assures that these proteins work at the right time and at the right place. Central key players within this control system are specific proteins termed kinases. Up to 500 different kinases are present within a single cell; each of them regulates a particular subset of proteins. They activate or inhibit proteins, route them to a specific cellular location, or block their interaction with other cell components. To transmit their orders, kinases label corresponding proteins with a small phosphate group. The underlying reaction mechanism seems to be the same for all known kinases: With the help of magnesium, kinases bind an ATP-molecule and cleave off one phosphate group, which is subsequently transferred to the protein. A small number of kinases, however, lack the ability to bind magnesium normally required for the reaction. As so-called "pseudokinases" they have so far been largely disregarded in research. Wrongfully, as shown now by an international team of scientists of the University of Texas (Dallas, USA), the Max Planck Institute for Biophysical Chemistry (Göttingen, Germany) and the Deutsches Elektronen Synchrotron (Hamburg, Germany).
The researchers investigated a pseudokinase - the CASK kinase - which seems to be actively involved in early development of the nervous system. CASK interacts directly with the protein neurexin, which is required for correct formation of synapses between nerve cells. Mice lacking CASK kinase die shortly after birth. Humans without CASK develop mental disorders and blindness. "But CASK can not bind magnesium and without magnesium kinases usually do not work. For us, this just did not add up", says neurobiologist Konark Mukherjee, one of the project leaders of the University of Texas. Therefore, the scientists simulated the reaction in the test tube step by step. To their surprise the CASK kinase transferred phosphate groups completely without magnesium. When the scientists added magnesium to the test tube, the kinase was in fact inhibited. But is CASK also functional in a living cell? Indeed, the researchers could prove that the kinase performs in the same way in nerve cells of rats. In biological terms, the improvised reaction mechanism of CASK makes perfect sense. During synapse formation nerve cells contain little to no magnesium. Kinases, which depend on magnesium for function would simply not be functional", explains Mukherjee.One protein - two functions
Dr. Carmen Rotte | Max-Planck-Gesellschaft
A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences