When it infects the lungs, the Legionnaire’s bacterium Legionella pneumophila causes acute pneumonia. The pathogen’s modus operandi is particularly ingenious: it infiltrates deliberately into cells of the human immune system and injects a host of proteins which then interfere in the normal cellular processes. Scientists from the Max Planck Institute of Molecular Physiology in Dortmund have now discovered how Legionella reprogrammes the cells to ensure its own survival and to propagate. They examined a protein used by the pathogen to divert the material transport within the cells for its own purposes. (Science, July 22, 2010)
During a Legionella infection, the bacteria are engulfed by immune cells and bound by a membrane in the cell interior. Legionella protects itself against destruction by releasing proteins that reprogramme the human cell and exploit it for its own purposes. One of these proteins is DrrA. Previous studies succeeded in demonstrating that DrrA diverts the material transport in human cells in the direction of the pathogen, using what are known as Rab proteins for this purpose.
Rab proteins are switch molecules that coordinate transport vesicles within cells. In this capacity, they ensure that these membrane-bound vesicles reach the correct destination at the right time. Of the total of 60 different Rab proteins, DrrA specifically uses the Rab1 molecule for its own purposes: it deposits Rab1 on the membrane enclosing the bacteria and activates it. As a result, part of the material transport of the human cell is diverted to the vesicle containing the bacterium.
The structural and biochemical analysis of DrrA led the Dortmund-based scientists to make an astonishing discovery: DrrA is not only capable of activating Rab1, it also appears to be able to extend its activated state. To this end, DrrA blocks the switching-off of Rab1 and the necessary recognition site for regulatory proteins by attaching an AMP molecule to Rab1. "The permanent activation of Rab1 by DrrA could ensure increased material transport in the direction of the Legionella containing compartment and hence support its survival," concludes Aymelt Itzen from the Max Planck Institute of Molecular Physiology."These results represent an example of how the molecular analysis of bacterial diseases can help us not only to understand the cellular mechanisms involved in an infection, but also the functioning of healthy cells," explains Roger Goody from the Dortmund Institute. In the case of Legionnaire’s disease, the study of the bacterial protein DrrA reveals how a human regulatory protein (Rab1) is activated in a targeted way and maintained in an active state. This raises the question as to whether Legionella devised this kind of regulation or whether healthy cells can also control material transport in a similar but hitherto unknown way.
Science, July 22, 2010 / DOI: 10.1126/science.1192276
Contact:Dr. Aymelt Itzen
Barbara Abrell | EurekAlert!
A novel synthetic antibody enables conditional “protein knockdown” in vertebrates
20.08.2018 | Technische Universität Dresden
Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover
There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.
The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
20.08.2018 | Information Technology
20.08.2018 | Life Sciences
20.08.2018 | Information Technology