Christopher J. Tonkin

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Cytoadherance of Plasmodium falciparum-infected erythrocytes in the brain, organs and peripheral microvasculature is linked to morbidity and mortality associated with severe malaria. Parasite-derived P. falciparum Erythrocyte Membrane Protein 1 (PfEMP1) molecules displayed on the erythrocyte surface are responsible for cytoadherance and undergo antigenic(More)
The phylum Apicomplexa are a group of obligate intracellular parasites responsible for a wide range of important diseases. Central to the lifecycle of these unicellular parasites is their ability to migrate through animal tissue and invade target host cells. Apicomplexan movement is generated by a unique system of gliding motility in which substrate(More)
Apicomplexan parasites depend on the invasion of host cells for survival and proliferation. Calcium-dependent signaling pathways appear to be essential for micronemal release and gliding motility, yet the target of activated kinases remains largely unknown. We have characterized calcium-dependent phosphorylation events during Toxoplasma host cell invasion.(More)
The phylum Apicomplexa comprises a group of obligate intracellular parasites of broad medical and agricultural significance, including Toxoplasma gondii and the malaria-causing Plasmodium spp. Key to their parasitic lifestyle is the need to egress from an infected cell, actively move through tissue, and reinvade another cell, thus perpetuating infection.(More)
  • Katrin Kremer, Dirk Kamin, Eva Rittweger, Jonathan Wilkes, Halley Flammer, Sabine Mahler +7 others
  • 2013
The basic organisation of the endomembrane system is conserved in all eukaryotes and comparative genome analyses provides compelling evidence that the endomembrane system of the last common eukaryotic ancestor (LCEA) is complex with many genes required for regulated traffic being present. Although apicomplexan parasites, causative agents of severe human and(More)
Malaria parasites invade host cells using actin-based motility, a process requiring parasite actin filament nucleation and polymerization. Malaria and other apicomplexan parasites lack Arp2/3 complex, an actin nucleator widely conserved across eukaryotes, but do express formins, another type of actin nucleator. Here, we demonstrate that one of two malaria(More)
Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), encoded by the var gene family, undergoes antigenic variation and plays an important role in chronic infection and severe malaria. Only a single var gene is transcribed per parasite, and epigenetic control mechanisms are fundamental in this strategy of mutually exclusive transcription. We show(More)
  • Fiona Angrisano, David T. Riglar, Angelika Sturm, Jennifer C. Volz, Michael J. Delves, Elizabeth S. Zuccala +15 others
  • 2012
Actin dynamics have been implicated in a variety of developmental processes during the malaria parasite lifecycle. Parasite motility, in particular, is thought to critically depend on an actomyosin motor located in the outer pellicle of the parasite cell. Efforts to understand the diverse roles actin plays have, however, been hampered by an inability to(More)
  • Michael J Coffey, Brad E Sleebs, Alessandro D Uboldi, Alexandra Garnham, Magdalena Franco, Nicole D Marino +14 others
  • 2015
Infection by Toxoplasma gondii leads to massive changes to the host cell. Here, we identify a novel host cell effector export pathway that requires the Golgi-resident aspartyl protease 5 (ASP5). We demonstrate that ASP5 cleaves a highly constrained amino acid motif that has similarity to the PEXEL-motif of Plasmodium parasites. We show that ASP5 matures(More)
UNLABELLED Key to the virulence of apicomplexan parasites is their ability to move through tissue and to invade and egress from host cells. Apicomplexan motility requires the activity of the glideosome, a multicomponent molecular motor composed of a type XIV myosin, MyoA. Here we identify a novel glideosome component, essential light chain 2 (ELC2), and(More)