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!
A novel socio-ecological approach helps identifying suitable wolf habitats
17.02.2017 | Universität Zürich
New, ultra-flexible probes form reliable, scar-free integration with the brain
16.02.2017 | University of Texas at Austin
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
17.02.2017 | Medical Engineering
17.02.2017 | Medical Engineering
17.02.2017 | Health and Medicine