Like our body every cell has a skeleton that provides it with a shape, confers rigidity and protects its fragile inner workings. The cytoskeleton is built of long protein filaments that assemble into networks whose overall architecture and fine detail can only be revealed with high resolution electron microscopy images. Researchers at the European Molecular Biology Laboratory (EMBL) and the University of Colorado have now obtained the first 3D visualization of a complete eukaryotic cell at a resolution high enough to resolve the cytoskeleton’s precise architectural plan in fission yeast. The image of this unicellular organism will be published in this week’s issue of the journal Developmental Cell and reveals remarkable insights into the fine structure of the cytoskeleton as well as its interactions with other parts of the cell.
A key component of the cytoskeleton are long, tube-like filaments called microtubules. They are dynamic structures built of constantly growing and shrinking rows of elementary proteins called tubulins. To increase their rigidity microtubules associate in bundles and interact with stabilizing proteins in complex networks, which are essential for many cellular processes such as polar growth.
“To really understand the architecture of the cytoskeleton you have to see the entire cell in three dimensions,” says Claude Antony, whose team carried out the research at EMBL, “but at the same time you need a very good resolution to be able to investigate its structural details. It is impossible to obtain such detailed images of a eukaryotic cell with normal microscopes.”
To bridge the gap between global overview and structural detail Antony’s team collaborated with yeast and electron microscopy expert Richard McIntosh at the University of Colorado. Using a technique called electron tomography, Johanna Höög, PhD student in Antony’s lab, took pictures of sequential sections of a yeast cell from many different angles through an electron microscope and combined these snapshots into a 3D reconstruction on the computer. A similar principle is used to generate brain scans.
For the first time they could see directly what previous studies in fission yeast only suggested. In times when a cell is not dividing a microtubule bundle consists of 4-5 individual filaments that are physically connected with each other via minute bridges likely formed by proteins. In the networks created through this crosslinking the orientation of microtubules is crucial. The filaments are polar structures, their two ends grow and shrink at different rates. The study created a precise map indicating the location of all growing and shrinking microtubule ends in the cell.
The images also shed light on other important functions of microtubules, revealing that the cytoskeleton determines the correct positioning of mitochondria, the energy-producing organelles, throughout the cell.
“Our 3D image of fission yeast can serve as a reference map of the cell for all biologists interested in its architecture,” says Johanna Höög. “You can extract information about all sorts of cellular structures and processes from it or use it to place findings into the spatial context of the cell.”
Yeast is one of the most commonly used model organisms in biology. It has many similarities with higher eukaryotes, including multicellular organisms. Many of the insights gained into its cellular organisation are likely to apply also to mammals. In mammalian nerve cells, for example, microtubule bundles similar to those observed in yeast are essential for the transmission of the signal from cell to cell.
Anna-Lynn Wegener | alfa
Cutting edge research for the industries of tomorrow – DFKI and NICT expand cooperation
21.03.2017 | Deutsches Forschungszentrum für Künstliche Intelligenz GmbH, DFKI
Molecular motor-powered biocomputers
20.03.2017 | Technische Universität Dresden
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
27.03.2017 | Earth Sciences
27.03.2017 | Life Sciences
27.03.2017 | Life Sciences