Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Cell Shape Changes during Mitosis

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

Prof. Dr. Frauke Melchior
Center for Molecular Biology of Heidelberg University
Phone +49 6221 54-6804

Communications and Marketing
Press Office, phone +49 6221 54-2311

Marietta Fuhrmann-Koch | idw
Further information:

More articles from Life Sciences:

nachricht First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife

nachricht Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Greater Range and Longer Lifetime

26.10.2016 | Power and Electrical Engineering

VDI presents International Bionic Award of the Schauenburg Foundation

26.10.2016 | Awards Funding

3-D-printed magnets

26.10.2016 | Power and Electrical Engineering

More VideoLinks >>>