Defining the mechanism and timing of Toxoplasma invasion effectors using X-ray fluorescence imaging

Toxoplasma gondii is an intracellular parasite that infects over half the world’s population and is the causative agent of toxoplasmosis – a condition extremely dangerous for developing foetuses and those with a weakened immune system (e.g. patients undergoing chemotherapy or infected with HIV). A common strategy for intracellular pathogens is to take control of host signalling networks in order to re-wire the response to its own requirements. A range of secreted agonists has recently been discovered in Toxoplasma gondii. We study the timing, dynamics and mechanism of these proteins, most recently the dense granule proteins GRA16 and GRA24. We aim to study the dynamics of GRA16 in vivo using high resolution X-ray fluorescence microscopy. By directly mapping these proteins in their native environment at high resolution, we are gaining insight into how, when and where these proteins emerge from the parasite and enter the host cell, for the first time.