This page contains automatically translated content.
Kassel biologists discover new protein that stabilizes cells
Image: University of KasselTardigrades are a biological phenomenon: Many species of these creatures, which are less than one millimeter in size, can withstand extreme heat as well as high radiation or temperatures below minus 20 degrees. They belong to the large group of so-called bilateria (two-sided animals), which also includes vertebrates and thus humans. But unlike almost all other representatives of this group, tardigrades, which occur both on land and in water, do not possess certain proteins, building blocks of the so-called cytoplasmic intermediate filaments (cytoplasmic IFs); these proteins stabilize the cells of the bilaterians by means of scaffold-like structures and thus make them more resistant. The tardigrades (Latin: Tardigrada) lost these proteins in the course of evolution. However, as the research group led by Prof. Dr. Georg Mayer, head of the Department of Zoology at the University of Kassel, together with colleagues from Leipzig led by Prof. Dr. Thomas Magin, has discovered, tardigrades replace these proteins with another protein.
For their studies, the biologists analyzed the complete set of active genes of a tardigrade species, Hypsibius dujardini. They found three so-called lamines, proteins that all bilaterians have in common, but which are usually located in the cell nucleus and not in the cytoplasm. One of these was not previously known from any other animal species. Provided with a marker, it was shown that the protein attaches itself like a belt to the inside of the cell membrane - but only in cells of the skin, mouth or other cells that are exposed to mechanical stress, such as in the area of the claws. From cell to cell, a lattice structure thus forms that stabilizes the tissue. The scientists named this newly discovered protein "cytotardin." They have now published the results in the research journal "eLife".
"We cannot yet say with certainty whether cytotardin is also responsible for the tardigrade's extreme resistance to heat, cold and radiation, but the assumption is obvious," says Prof. Georg Mayer. "What is certain is that nature is using a trick here that has been shown time and again in other animals: If a certain endowment is lost in the course of evolution - in this case, cytoplasmic IFs - but the capability is still in demand - in this case, cell stability - the organism reworks other endowments to accomplish the task. In other words, nature always finds a solution." The tardigrades were helped here by the fact that they have a short life cycle and thus a high substitution rate, in other words: there are many opportunities for mutations.
Lars Hering, Jamal-Eddine Bouameur, Julian Reichelt, Thomas M. Magin, Georg Mayer: Novel origin of lamin-derived cytoplasmic intermediate filaments in tardigrades. eLife 2016;5:e11117.
Link to article:http://elifesciences.org/content/5/e11117v3
Image of a tardigrade with visualization of labeled cells at:
http://www.uni-kassel.de/uni/fileadmin/datas/uni/presse/anhaenge/2015/Baertierchen.png
Caption: "A scanning electron micrograph of the tardigrade Hypsibius dujardini, overlaid with an image of fluorescently labeled cytotardin, illustrates the distribution of the protein in the animal's skin (not to scale)." Image: Irene Minich, Julian Reichelt, Vladimir Gross and Lars Hering.
Image by Prof. Dr. Georg Mayer (Photo: private) at
http://www.uni-kassel.de/uni/fileadmin/datas/uni/presse/anhaenge/2015/Georg_Mayer1.jpg
Contact:
Prof. Dr. Georg Mayer
University of Kassel
Department of Zoology
Tel.: +49 (0)561 804-4805
E-mail: georg.mayer@uni-kassel.de