Key adjustment enables parasite shape-shifting

August 4, 2014
T. brucei parasites in the trypomastigote stage (left) adopt a very different shape compared with the epimastigote-like cells induced by suppression of a key protein (right). Credit: Hayes et al., 2014

Crafty parasites frequently undergo dramatic shape changes during their life cycles that enable them to adapt to different living conditions and thrive. But these transformations might not be as difficult as they appear, according to a study in The Journal of Cell Biology.

African "sleeping sickness" is a disease caused by a species of parasite known as Trypanosoma brucei that is transmitted by the . The single-celled parasite has a kinetoplast, which houses the cell's mitochondrial DNA, and a protruding flagellum that is crucial for cell movement. T. brucei undergoes major changes in shape and form during its developmental cycle. In one phase, known as the trypomastigote stage, the kinetoplast is located posterior to the nucleus and almost all of the flagellum is connected to the cell. In the epimastigote stage, on the other hand, the kinetoplast is anterior to the nucleus, and only part of the flagellum is fastened to the cell. T. brucei's close relatives come in many different shapes, indicating that the parasites have also altered their morphology during evolution.

When researchers from the University of Oxford reduced the expression of a protein called ClpGM6 in T. brucei trypomastigotes, the switched to an epimastigote-like morphology. The kinetoplast was close to the nucleus or anterior to it, and a long section of the flagellum extended beyond the cell. The parasites weren't identical to epimastigotes—they lacked a distinctive surface protein found at this life stage—but they were able to survive and reproduce for more than 40 generations.

The video will load shortly
Researchers show that suppressing expression of a key protein causes major changes in the shape of T. brucei (shown here), the parasite that causes African sleeping sickness. Credit: Hayes et al., 2014

ClpGM6 resides in the flagellar attachment zone and likely helps fasten the to the cell body. Loss of ClpGM6 shortened the flagellar attachment zone, which helps determine cell size and shape. The study suggests that dramatic morphological changes during the life cycle and during parasite evolution may result from adjustments in the levels of a few key proteins, rather than from wholesale changes in the parasite's protein or DNA content.

Explore further: New treatment for African sleeping sickness comes closer

More information: Hayes, P., et al. 2014. J. Cell Biol. doi:10.1083/jcb.201312067

Related Stories

New treatment for African sleeping sickness comes closer

November 6, 2013

Researchers at Umeå University have identified drugs targeting infections of the parasite Trypanosoma brucei and are thereby well on the way to find a cure against African sleeping sickness. This is the kernel of a thesis, ...

Parasite helps itself to sugar

July 8, 2013

Trypanosoma brucei, the parasite that causes sleeping sickness, is transmitted to mammals by the tsetse fly, and must adapt to the divergent metabolisms of its hosts. A new study shows how it copes with the frugal diet offered ...

Sleeping sickness by stealth

February 5, 2013

(Medical Xpress)—Stealth is a well-known concept in military tactics. Almost since the invention of radar, the hunt began for counter-technologies to hide aircraft and missiles from detection – most successfully by modifying ...

Recommended for you

Immune defense without collateral damage

January 23, 2017

Researchers from the University of Basel in Switzerland have clarified the role of the enzyme MPO. In fighting infections, this enzyme, which gives pus its greenish color, produces a highly aggressive acid that can kill pathogens ...

Provocative prions may protect yeast cells from stress

January 23, 2017

Prions have a notorious reputation. They cause neurodegenerative disease, namely mad cow/Creutzfeld-Jakob disease. And the way these protein particles propagate—getting other proteins to join the pile—can seem insidious.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.