Featured Research

from universities, journals, and other organizations

Malaria pathogen's cellular skeleton under super-microscope

Date:
April 17, 2014
Source:
Helmholtz Centre for Infection Research
Summary:
The tropical disease malaria is caused by the Plasmodium parasite. For its survival and propagation, Plasmodium requires a protein called actin. Scientists used high-resolution structural biology methods to investigate the different versions of this protein in the parasite. Their results may in the future contribute to the development of tailor-made drugs against malaria -- a disease that causes more than half a million deaths per year.

The Anopheles mosquito transmits the Plasmodium parasite, which causes malaria.
Credit: CDC/James Gathany

The tropical disease malaria is caused by the Plasmodium parasite. For its survival and propagation, Plasmodium requires a protein called actin. Scientists of the Helmholtz Centre for Infection Research (HZI) in Germany used high-resolution structural biology methods to investigate the different versions of this protein in the parasite in high detail. Their results, published in the scientific journal PLOS Pathogens, may in the future contribute to the development of tailor-made drugs against malaria-a disease that causes more than half a million deaths per year.

Malaria is a life-threatening disease. According to World Health Organization estimates, around 207 million cases of malaria occurred in 2012. Children in Africa are at an especially high risk, and there is no approved vaccination to date. The disease is caused by Plasmodium parasites-single-celled parasites, which are transmitted by mosquitos. The pathogen enters the human body through a bite and induces typical symptoms like periodic fevers, nausea, and headaches.

To enter human cells and leave them again, the parasites need to be motile. To this end, they use a structural protein called actin. Actin is found in nearly all living organisms where it is one of the most abundant proteins. Inside cells, it assumes numerous tasks: It confers stability, allows cell division, and makes movement of single cells possible. The dynamical behaviour needed for these processes is enabled by individual globular actin molecules assembling together to form thread-like structures called filaments. The malaria parasite possesses two versions of actin, actin I and actin II, which differ substantially from each other. Even though these structural proteins are crucial for the pathogen's infectivity, researchers have so far not been able to demonstrate filament formation in the parasite.

Scientists of the HZI, the German Electron Synchrotron (DESY) and the European Molecular Biology Laboratory (EMBL), together with international partners, now succeeded in detecting filament assembly of the parasite actin II proteins. For this, they used electron microscopy, which overcomes the resolution limit of classical light microscopy. Male malaria parasites from which the scientists had deleted actin II were not able to form mature germ cells and consequently could not reproduce and propagate. To have only one actin variant is apparently not sufficient for this process. How filaments contribute to germ cell maturation is still unclear. But why do the two proteins show such different behaviour?

To answer this question, the research team deciphered the structure of the globular actin proteins using X-radiation. "We were able to determine the structures of actin I and actin II at very high resolutions-down to 1.3 and 2.2 Εngstrφm, respectively. With this, we are in the range of single atoms," says the project leader Prof Inari Kursula. "The structures show us that the two variants differ more from each other than actins in any other known living organism do." The high resolution enabled the researchers to identify areas within the proteins that cause the different behaviour. "We now understand that Plasmodium actin filaments are very different from other actin filaments, like for example from those found in humans, and that they are assembled in a very different manner. Now that we know the structural basis for this, we can look for ways to specifically interfere with the parasite cytoskeleton," says Kursula. This knowledge might in the future contribute to designing tailor-made anti-malarial medication.


Story Source:

The above story is based on materials provided by Helmholtz Centre for Infection Research. Note: Materials may be edited for content and length.


Journal Reference:

  1. Juha Vahokoski, Saligram Prabhakar Bhargav, Ambroise Desfosses, Maria Andreadaki, Esa-Pekka Kumpula, Silvia Muρico Martinez, Alexander Ignatev, Simone Lepper, Friedrich Frischknecht, Inga Sidιn-Kiamos, Carsten Sachse, Inari Kursula. Structural Differences Explain Diverse Functions of Plasmodium Actins. PLoS Pathogens, 2014; 10 (4): e1004091 DOI: 10.1371/journal.ppat.1004091

Cite This Page:

Helmholtz Centre for Infection Research. "Malaria pathogen's cellular skeleton under super-microscope." ScienceDaily. ScienceDaily, 17 April 2014. <www.sciencedaily.com/releases/2014/04/140417191733.htm>.
Helmholtz Centre for Infection Research. (2014, April 17). Malaria pathogen's cellular skeleton under super-microscope. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2014/04/140417191733.htm
Helmholtz Centre for Infection Research. "Malaria pathogen's cellular skeleton under super-microscope." ScienceDaily. www.sciencedaily.com/releases/2014/04/140417191733.htm (accessed August 29, 2014).

Share This




More Health & Medicine News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

3 Things To Know About The Ebola Outbreak's Progression

3 Things To Know About The Ebola Outbreak's Progression

Newsy (Aug. 29, 2014) — Here are three things you need to know about the deadly Ebola outbreak's progression this week. Video provided by Newsy
Powered by NewsLook.com
Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) — State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Who Could Be Burnt by WHO's E-Cigs Move?

Who Could Be Burnt by WHO's E-Cigs Move?

Reuters - Business Video Online (Aug. 28, 2014) — The World Health Organisation has called for the regulation of electronic cigarettes as both tobacco and medical products. Ciara Lee looks at the impact of the move on the tobacco industry. Video provided by Reuters
Powered by NewsLook.com
CDC Director On Ebola Outbreak: 'It's Worse Than I Feared'

CDC Director On Ebola Outbreak: 'It's Worse Than I Feared'

Newsy (Aug. 28, 2014) — CDC director Tom Frieden says the Ebola outbreak is even worse than he feared. But he also said there's still hope to contain it. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins