Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The role of the cellular entry point of anthrax identified

03.12.2012
Researchers at the University of Geneva, Switzerland, demonstrate that the receptors that bind the toxin of this bacterium control how cell division is oriented

Anthrax uses a receptor on the surface of cells to inject its lethal toxins. However, the physiological function of this receptor, named Anthrax Toxin Receptor 2a (Antxr2a), remained unknown until now. A team led by Marcos Gonzalez-Gaitan, a professor at the University of Geneva (UNIGE), Switzerland, in collaboration with Gisou van der Goot at EPFL (École Polytechnique Fédérale de Lausanne), reveals that Antxr2a actually plays a role in embryonic development, orienting cell division along a specific plane, which is a prelude to the formation of future tissues and organs.

At the cellular level, this receptor exerts traction on the system that allows chromosomes to separate to opposite poles, the mitotic spindle, to position it along the plane of division. These results are presented in the journal Nature Cell Biology.

Anthrax is a particularly virulent germ once a person is infected by inhaling its spores. The severity of symptoms, which affect various organs, is mainly due to bacterial toxins which are lethal to cells. It is by attempting to understand how the bacillus' toxins enter cells that the Antxr2a receptor was discovered. Otherwise, its physiological role would not have been identified at present.

A cap of proteins indicates the plane of division
During animal development, the orientation of cell division along a specific plane is important for the organization of the different tissues and the generation of cellular diversity. This orientation is provided by the position of the mitotic spindle in the cell that is about to divide. This temporary assembly of microtubules forms an actual spindle between opposite poles of the cell in order to guide the migration of each set of chromosomes.

"When the cell receives an external signal to initiate its division, a cascade of biochemical events is launched to transmit the message to the interior of the cell and have it carried out. We knew that an external signal, a protein called Wnt, was necessary to properly position the mitotic spindle, but knew nothing of the intracellular messengers involved," explains Marcos Gonzalez-Gaitan, Professor in the Departments of Biochemistry and Molecular Biology at the University of Geneva.

This has now been accomplished. The scientist and his group have established the complete sequence of intracellular events allowing the mitotic spindle to align itself along the general plane of division. They conducted their experiments on zebrafish embryos, a model system in developmental studies. "Once Wnt binds to the cell membrane, different molecular agents prompt the formation of a layer of filamentous proteins along the cell membrane, at the site of the future plane of division," explains Irinka Castanon, first author of the article.

The anthrax receptor used as a control lever
This internal 'cap' associates itself in turn with the Antxr2a receptors, known to bind the anthrax toxin. The accumulation of these receptors will thus form a second layer, superimposed on the first. Everything is now in place for the final phase: "The Antxr2a receptors recruit in turn 'motor' proteins capable of attaching themselves to the mitotic spindle and pulling it towards the internal cap," states Marcos Gonzalez-Gaitan. Motor proteins probably act by travelling back up along the cap's filaments, allowing the alignment of the spindle with the plane of cell division.

In mammals, the Antxr2a receptor is also involved in the formation and proliferation of blood vessels. "It is therefore possible that the role of this receptor in the orientation of cell division is not restricted solely to embryonic development," states the professor, who is a member of two Swiss National Research Programs: Frontiers in Genetics, and Chemical Biology.

Marcos Gonzalez-Gaitan | EurekAlert!
Further information:
http://www.unige.ch

More articles from Life Sciences:

nachricht New catalyst controls activation of a carbon-hydrogen bond
21.11.2017 | Emory Health Sciences

nachricht The main switch
21.11.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>