The mechanical basis of mitosis has only been understood in fragments so far. Scientists at Technische Universität Dresden have now been able to add another piece to the puzzle of cell biological mechanisms, as they report in the latest issue of the renowned scientific journal “Cell” on March 5, 2015.
When cells divide, their genetic information is passed on to both daughter cells in a highly complex process. Thereby, an important role is played by small, cylindrical protein tubes, called microtubules. They form the scaffold of the spindle apparatus helping to distribute the genome in the chromosomes to the two daughter cells when cells divide.
Besides their mission of docking onto the chromosomes directly and pulling them apart, microtubules are also of great importance for stabilizing the spindle apparatus. To this end the microtubules overlap at the centre of the cell, connecting the opposite spindle poles.
When cells divide, it can be observed that these overlapping microtubules are initially made to slide in relation to one another by so-called motor proteins, but then stop before actually separating. Until now, scientists have only been able to explain the mechanism that inhibits their movement and stops the sliding in parts.
In cooperation with scientists from the Netherlands (Wageningen University and AMOLF), an international group of scientists around Professor Dr. Stefan Diez (Heisenberg Professor at ZIK B CUBE – Center for Molecular Bioengineering at TU Dresden, and group leader at the Max Planck Institute of Molecular Cell Biology and Genetics) has now been able to show that a well-known principle of physics is also relevant in biology: Weakly binding proteins which preferably accumulate between overlapping microtubules behave like diffusing gas particles in a closed container.
Those gas particles respond with rising pressure to a reduction in volume. This simple principle, as familiar from the ideal gas law as it is from common household bicycle pumps, is also how the weakly binding proteins create an ever growing counter-pressure between the overlapping microtubules as they slide apart. This causes the movement to decelerate and stops the sliding. This biomolecular mechanism corresponds to the principle of a gas spring .
The scientists have been able to demonstrate this mechanism in experiment and theory. They have also successfully managed to directly measure the resulting forces by means of optical tweezers. And they have finally been able to show that the gas-like pressure of the weakly binding proteins is strong enough to compensate the power of the motor proteins and keep the overlapping microtubules from falling apart.
This not only means that a minimal mechanism for stabilizing overlapping microtubules has been found and experimentally proven, but also that a further generally applicable mechanism has been added to the repertoire of cell biological mechanisms of action.
The study was published online in the renowned scientific journal "Cell" on 5 March 2015 and will appear in the printed issue on 12 March 2015.
Zdenek Lansky, Marcus Braun, Annemarie Lüdecke, Michael Schlierf, Pieter Rein ten Wolde, Marcel E Janson, Stefan Diez, Diffusible crosslinkers generate directed forces in microtubule networks, DOI:10.1016/j.cell.2015.01.051
Information for journalists:
Prof. Dr. Stefan Diez
Heisenberg-Professorship for BioNano Tools
Technische Universität Dresden
ZIK B CUBE - Center for Molecular Bioengineering
Tel.: +49 (0) 351 463 43010
Fax: +49 (0) 351 463 40322
About B CUBE at the TU Dresden
The Center for Innovation Competence (ZIK) B CUBE – Center for Molecular Bioengineering was founded in 2008 in conjunction with funding by the BMBF-program „Unternehmen Region“. The center is dedicated to investigate and engineer biological materials along the three main axes BioProspecting, BioNano Tools and Biomimetic Materials, thereby contributing significantly to the profile of the TU Dresden in the fields of modern biotechnology and biomedicine.
Caption: The upper part of the figure shows a schematic diagram of the movement of two overlapping microtubules (red and orange) in combination with typical fluorescence microscopy images. The lower part of the figure shows a gas spring, the macroscopic counterpart of the biomolecular system, where gas is compressed by the impact of an external force and expands again later as soon as the external force is reduced.
Kim-Astrid Magister | Technische Universität Dresden
Protein 'spy' gains new abilities
28.04.2017 | Rice University
How Plants Form Their Sugar Transport Routes
28.04.2017 | Universität Heidelberg
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Life Sciences
28.04.2017 | Life Sciences
28.04.2017 | Life Sciences