New paper in PLoS Biology
All biological membranes are composed of lipids, and most organisms across the tree of life use a relatively limited repertoire of lipids. A recent study performed in the laboratory of Dr. Nishith Gupta (Department of Molecular Parasitology, Humboldt University of Berlin) reveals a new building block, called phosphatidylthreonine (PLoS Biology, 2015). This lipid was discovered in the protozoan parasite /Toxoplasma/, the causative agent of Toxoplasmosis in people that undergo immune suppression. The researchers identified this unusual component in membrane extracts by a very sensitive detection technique, gas chromatography coupled with mass spectrometry. The team shows that phosphatidylthreonine is made by a previously unrecognized enzyme, which apparently evolved from a close relative present in all organisms, including humans. Removing this lipid from the parasites by genetic manipulation slowed the expansion of the parasite, and infected laboratory mice remained healthy.
Infection with weakened /Toxoplasma/parasites protected mice from future infection, and might be used as a vaccine in animals, such as cats and sheep. The absence of this lipid in the infected hosts also shows promise for the development of tailored drugs. Apart from the direct implications for the rational design of anti-infectives this discovery also indicates that variations in lipid compositions of biomembranes might occur more frequently than previously thought.
Phosphatidylthreonine and lipid-mediated control parasite virulence
R.D. Arroyo-Olarte, J.F. Burrowers, A. Kuchipudi, J.B. Helms, A. Biswas, I.R. Dunay, R. Lucius, and N. Gupta (2015)
PLoS Biol., 13(e1002288).