Characterising a novel family of amino acid transporters in Toxoplasma gondii.

Apicomplexans are a phylum of unicellular eukaryotic parasites that cause a range of diseases in humans, including toxoplasmosis and malaria. Other apicomplexan parasites afflict animal species, causing significant animal suffering and economic loss in the livestock industry. Parasites, by definition, rely on their hosts as a source of nutrients. Disruption of nutrient acquisition therefore represents an avenue by which to halt parasite replication and cure infections. A major route through which cells acquire nutrients (and remove waste products and toxins) is via plasma membrane-localised solute transporter proteins. The plasma membrane transporters of apicomplexans are currently not well characterised.

My research has focused on a group of transporters known as the Novel Putative Transporter (NPT) family. Initially identified in Plasmodium falciparum, I have found that this family is present throughout apicomplexans and their closest free-living relatives. Using Toxoplasma gondii as a model system, I determined that all the NPTs expressed in the disease-causing stage of the T. gondii life cycle localise to the plasma membrane. Using a CRISPR/Cas9 genome editing approach, I determined which of the 16 NPT-family proteins in T. gondii are important for parasite survival. I demonstrated that one of these has a critical function in amino acid transport across the parasite plasma membrane.

Together, my research demonstrates key roles for a novel family of plasma membrane solute transporters in T. gondii biology, including in the uptake of essential amino acids.


Kathryn graduated with a Bachelor of Philosophy (Science) with first class Honours and a University Medal from ANU in 2013. She commenced her conjoint PhD/MChD degree in 2014, undertaking her PhD under the supervision of Dr Giel van Dooren and Prof. Kiaran Kirk.