Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mitosis mystery solved as role of key protein is confirmed

18.02.2014
Researchers from Warwick Medical School have discovered the key role of a protein in shutting down endocytosis during mitosis, answering a question that has evaded scientists for half a century.

The study, published today in the journal eLife, is the first to outline the role of actin, a protein, in shutting down clathrin-dependent endocytosis during mitosis.


This shows restarted endocytosis in a mitotic cell.

Credit: Royle/University of Warwick

Endocytosis is the process by which cells absorb molecules that are too large to pass through the plasma membrane, such as proteins. Clathrin-dependent endocytosis is the most common route for this. Clathrin, a protein, forms a pit on the inner surface of the membrane which allows the cell to engulf and bring in a small volume of fluid from outside the cell.

The team, led by Dr Steve Royle, were able to answer a question that was first asked in 1965 by American cell biologist, Don Fawcett. Fawcett became aware that clathrin-dependent endocytosis shuts down during mitosis, but the understanding of why it happens has eluded researchers until now.

In the latter part of the 20th Century, two competing theories emerged. One theory suggested that the tension of the plasma membrane is too high for endocytosis to occur. The other theory stated that the cell actually switches off the proteins involved by a process of mitotic phosphorylation, the addition of a phosphate group to the cell proteins.

More recently, scientists found that in non-dividing cells, when membrane tension is high, endocytosis can still occur because actin can be recruited to help clathrin to overcome the high tension in the membrane.

The Warwick team measured membrane tension in mitotic cells and found it to be much higher than in non-dividing cells, thus sparking the investigation into why actin is not recruited to help out in this case. They found that during mitosis, actin is busy forming a stiff cortex in the cells and so cannot be used to help out endocytosis. In other words, actin is needed, but is unavailable for use.

By tricking the cell into making actin available during mitosis, the researchers were able to restart endocytosis in mitotic cells. The paper also describes how mitotic phosphorylation does not inhibit the process, arguing against the alternative theory.

The newfound appreciation for the role played by actin opens the door for further developments, both for researchers and for possible clinical applications.

Dr Royle explained, "The implications for human health are truly fascinating; by knowing the role played by actin we can look to use it to restart endocytosis during cell division. That could mean that we're able to make dividing cells receptive to pharmaceuticals or other medical treatments in a way that we haven't before."

"It also opens up other strands of research and questions for our field. For instance, how does the cell know that the membrane tension is too high for normal endocytosis? When and how does it call in actin? There is plenty we are yet to discover."

The research was funded by the Biotechnology and Biological Sciences Research Council (BBSRC).

Luke Harrison | EurekAlert!
Further information:
http://www.warwick.ac.uk

More articles from Life Sciences:

nachricht Protein scaffold
27.05.2015 | Okinawa Institute of Science and Technology (OIST) Graduate University

nachricht Seeing the action
27.05.2015 | University of California - Santa Barbara

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Advance in regenerative medicine

The only professorship in Germany to date, one master's programme, one laboratory with worldwide unique equipment and the corresponding research results: The University of Würzburg is leading in the field of biofabrication.

Paul Dalton is presently the only professor of biofabrication in Germany. About a year ago, the Australian researcher relocated to the Würzburg department for...

Im Focus: Basel Physicists Develop Efficient Method of Signal Transmission from Nanocomponents

Physicists have developed an innovative method that could enable the efficient use of nanocomponents in electronic circuits. To achieve this, they have developed a layout in which a nanocomponent is connected to two electrical conductors, which uncouple the electrical signal in a highly efficient manner. The scientists at the Department of Physics and the Swiss Nanoscience Institute at the University of Basel have published their results in the scientific journal “Nature Communications” together with their colleagues from ETH Zurich.

Electronic components are becoming smaller and smaller. Components measuring just a few nanometers – the size of around ten atoms – are already being produced...

Im Focus: IoT-based Advanced Automobile Parking Navigation System

Development and implementation of an advanced automobile parking navigation platform for parking services

To fulfill the requirements of the industry, PolyU researchers developed the Advanced Automobile Parking Navigation Platform, which includes smart devices,...

Im Focus: First electrical car ferry in the world in operation in Norway now

  • Siemens delivers electric propulsion system and charging stations with lithium-ion batteries charged from hydro power
  • Ferry only uses 150 kilowatt hours (kWh) per route and reduces cost of fuel by 60 percent
  • Milestone on the road to operating emission-free ferries

The world's first electrical car and passenger ferry powered by batteries has entered service in Norway. The ferry only uses 150 kWh per route, which...

Im Focus: Into the ice – RV Polarstern opens the arctic season by setting course for Spitsbergen

On Tuesday, 19 May 2015 the research icebreaker Polarstern will leave its home port in Bremerhaven, setting a course for the Arctic. Led by Dr Ilka Peeken from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) a team of 53 researchers from 11 countries will investigate the effects of climate change in the Arctic, from the surface ice floes down to the seafloor.

RV Polarstern will enter the sea-ice zone north of Spitsbergen. Covering two shallow regions on their way to deeper waters, the scientists on board will focus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International symposium: trends in spatial analysis and modelling for a more sustainable land use

20.05.2015 | Event News

15th conference of the International Association of Colloid and Interface Scientists

18.05.2015 | Event News

EHFG 2015: Securing health in Europe. Balancing priorities, sharing responsibilities

12.05.2015 | Event News

 
Latest News

Researchers develop intelligent handheld robots

27.05.2015 | Power and Electrical Engineering

"Hidden" fragrance compound can cause contact allergy

27.05.2015 | Health and Medicine

Supernovas help 'clean' galaxies

27.05.2015 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>