Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cell Shape Changes during Mitosis

12.02.2013
Heidelberg scientists study transient degradation of an actin regulator

Scientists at the Center for Molecular Biology of Heidelberg University have gained new insight into the process of mitosis in mammalian cells.


Immunofluorescence staining of a cell in early mitosis with normal (right) and with elevated (left) levels of Eps8. The actin cytoskeleton is shown in green and DNA in red. Blue colours depicts a specific marker for mitosis.

Credits: Dr. Achim Werner

Researchers under the direction of Prof. Dr. Frauke Melchior, in collaboration with colleagues from Göttingen, Milan and Memphis, have succeeded in deciphering a heretofore unknown mechanism that plays a key role in cell shape changes during mitosis. They investigated the transient degradation of a protein that regulates specific structures of the mechanical scaffold of the cell, the actin cytoskeleton. The results of the research on this actin regulator were published in the journal “Nature Cell Biology”.

Equally dividing the chromosomes between two daughter cells during mitosis is a multi-step and precisely controlled process. After break-down of the cell nucleus and mitotic spindle formation, the chromosomes pull apart and travel towards the spindle poles. Two cell nuclei are then formed and the cell splits into two daughter cells. According to Prof. Melchior, it has long been known that the cell’s actin cytoskeleton – threadlike cellular structures made up of the structural protein actin – is also a major regulating component of this process. Due to dynamic changes before, during and after the mitosis phase, the actin cytoskeleton contributes to the mechanical requirements for the symmetrical distribution of chromosomes to the two new daughter cells. “We barely understand how and why the actin network of the cell changes, especially in the early phases of mitosis. Of particular interest is how cells assume a round shape when cell division starts and then flatten out again once it ends”, explains Dr. Achim Werner, a key contributing member of Prof. Melchior's research group.

The Heidelberg researchers were now able to show that the transient degradation of an actin regulator in the cell's cytoskeleton, known as Eps8, plays an important role in the mitosis phase. The degradation of Eps8, which only appears to be a “stable” protein, is mediated by a little known Ubiquitin E3 ligase. “If you turn off this degradation mechanism, cell rounding is delayed and the early phases of mitosis slow down. If, however, there is too little Eps8 during the later phase of mitosis, the shape of the cell deforms markedly”, continues Dr. Werner. Thus, precise control of Eps8 levels contributes to the structural changes that eukaryotic cells must undergo to distribute the genetic information correctly to the two daughter cells. “Our work once again demonstrates that controlled protein degradation is a critical component in the regulation of cellular processes”, says Prof. Melchior.

The research was conducted within the framework of the DKFZ-ZMBH Alliance, the strategic cooperation between the German Cancer Research Center (DKFZ) and the Center for Molecular Biology of Heidelberg University (ZMBH). Contributors to the project included researchers from the Max Planck Institute for Biophysical Chemistry in Göttingen and the University Medical Center Göttingen, the FIRC Institute of Molecular Oncology (IFOM) in Milan and the University of Milan, and the Howard Hughes Medical Institute – St. Jude Children’s Research Hospital – in Memphis.
Original publication:
A. Werner, A. Disanza, N. Reifenberger, G. Habeck, J. Becker, M. Calabrese, H. Urlaub, H. Lorenz, B. Schulman, G. Scita & F. Melchior: SCF-Fbxw5 mediates transient degradation of actin remodeller Eps8 to allow proper mitotic progression, Nature Cell Biology (published online 13 January 2013), doi:10.1038/ncb2661

Contact:
Prof. Dr. Frauke Melchior
Center for Molecular Biology of Heidelberg University
Phone +49 6221 54-6804
f.melchior@zmbh.uni-heidelberg.de

Communications and Marketing
Press Office, phone +49 6221 54-2311
presse@rektorat.uni-heidelberg.de

Marietta Fuhrmann-Koch | idw
Further information:
http://www.uni-heidelberg.de

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>