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 Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory

nachricht How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

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...

Im Focus: Tracing down linear ubiquitination

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...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

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...

Im Focus: Researchers Imitate Molecular Crowding in Cells

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>