Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How Rickettsial Pathogens Break Into Cells

16.12.2005


New research by a team of scientists in France and the United States has identified both the bacterial and host receptor proteins that enable Rickettsia conorii, the Mediterranean spotted fever pathogen to enter cells. Understanding how this bacterium interacts with the cells of its host could lead to new therapeutic strategies for diseases caused by related pathogens, including Rocky Mountain spotted fever and typhus.



Pascale Cossart, an HHMI international research scholar at the Pasteur Institute in Paris, together with her postdoctoral fellow Juan Martinez and collaborators in Paris and at Case Western Reserve University in Cleveland, Ohio, has identified the first receptor for a Rickettsial bacterium. Their findings will be reported in the December 16, 2005, issue of the journal Cell.

Rickettsial bacteria are transmitted by fleas, ticks, and lice to humans and other mammals, where they can cause dangerous and sometimes fatal infections. There are two types of Rickettsial pathogens—the spotted fever group, which includes the Rickettsia conorii bacteria studied by Cossart and her colleagues, and the typhus group. Both must live inside cells to survive. Rickettsia have been classified by the National Institute of Allergy and Infectious Diseases (NIAID) as agents with potential for use as tools for bioterrorism.


Mediterranean spotted fever is transmitted by a dog tick. The symptoms are generally mild and respond to antibiotics that shorten the course of the disease. But serious complications occur as much as 10 percent of the time, usually in patients who are elderly or who have some other underlying disease. Left untreated, Mediterranean spotted fever can be deadly.

Cossart and her team demonstrated that the Ku70 protein on the surface of host cells is critical for R. conorii to enter the cell, making it the first Rickettsial receptor ever identified. “This receptor is a subunit of a protein complex present mainly in the nucleus, but also in the cell cytoplasm and at the cell membrane,” said Cossart. “We have thus used several approaches to establish our findings definitively.” Ku70 is probably not the only receptor involved in bacterial entry, she noted.

The researchers found that R. conorii specifically binds to Ku70, and that binding and recruitment of Ku70 at the surface of the host cell are important events in R. conorii’s invasion of mammalian cells. In addition, since Ku70 has previously been shown to control cell death, the new findings suggest that Rickettsia, which—like several other intracellular parasites—prevent cell death in order to multiply inside living cells, may also use this property of their receptor for a succesful infection.

“We found that Ku70 interacts with a bacterial protein called rOmpB, which is present on the surface of Rickettsia bacteria,” Cossart said. “The mechanism underlying this interaction remains unclear, so we are now investigating how rOmpB, expressed by R. conorii, interacts with Ku70 and allows bacterial entry.”

Her team has already shown that Ku70 has to be present in certain well-organized regions of the cell membrane called rafts, and that the protein modifier called ubiquitin modifies Ku70 as soon as the bacteria interact with it. This step is critical for cell entry. “Whether other Rickettsia and other pathogens use Ku70 as a receptor is still unknown,” Cossart said.

Jennifer Donovan | EurekAlert!
Further information:
http://www.hhmi.org

More articles from Life Sciences:

nachricht Discovery of a Key Regulatory Gene in Cardiac Valve Formation
24.05.2017 | Universität Basel

nachricht Carcinogenic soot particles from GDI engines
24.05.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>