Apical membrane antigen 1 (AMA1) of the human malaria parasite Plasmodium falciparum has been implicated in invasion of the host erythrocyte. It interacts with malarial rhoptry neck (RON) proteins in the moving junction that forms between the host cell and the invading parasite. Agents that block this interaction inhibit invasion and may serve as promising leads for anti-malarial drug developme...

Host cell infection by apicomplexan parasites plays an essential role in lifecycle progression for these obligate intracellular pathogens. For most species, including the etiological agents of malaria and toxoplasmosis, infection requires active host-cell invasion dependent on formation of a tight junction - the organising interface between parasite and host cell during entry. Formation of this...

The most deadly Apicomplexan parasite is Plasmodium falciparum because it causes the globally spread human malaria especially in Africa. Like other members of Apicomplexa, Plasmodium is an intracellular parasite that uses an elaborate complex of apical secretory organelles (rhoptries, micronemes and dense granules) to invade its host cells and immediately accommodate itself in a parasitophorous...

The intracellular parasite Toxoplasma gondii enjoys a wide host range and is adept at surviving in both naive and activated macrophages. Previous studies have emphasized the importance of the active serine-threonine protein kinase rhoptry protein 18 (ROP18), which targets immunity-related GTPases (IRGs), in mediating macrophage survival and acute virulence of T. gondii in mice. Here, we demonst...

Toxoplasma gondii possesses a highly polarized secretory system, which efficiently assembles de novo micronemes and rhoptries during parasite replication. These apical secretory organelles release their contents into host cells promoting parasite invasion and survival. Using a CreLox-based inducible knock-out strategy and the ddFKBP over-expression system, we unraveled novel functions of the cl...

Babesia bovis merozoite apical membrane polypeptide Bv60 was found to be rhoptry associated by immuno-electron microscopy and was redesignated rhoptry-associated protein 1 (RAP-1). The N-terminal 300 amino acids of RAP-1 have a high level of sequence similarity to the same N-terminal region of p58, its homolog from Babesia bigemina. However, the interspecies conserved sequences did not include ...

NF-κB is an integral component of the immune response to Toxoplasma gondii. Although evidence exists that T. gondii can directly modulate the NF-κB pathway, the parasite-derived effectors involved are unknown. We determined that type II strains of T. gondii activate more NF-κB than type I or type III strains, and using forward genetics we found that this difference is a result of the polymorphi...

The malaria parasite Plasmodium knowlesi, previously associated only with infection of macaques, is now known to infect humans as well and has become a significant public health problem in Southeast Asia. This species should therefore be targeted in vaccine and therapeutic strategies against human malaria. Apical Membrane Antigen 1 (AMA1), which plays a role in Plasmodium merozoite invasion of ...

Proteases of the malaria parasite Plasmodium falciparum have long been investigated as drug targets. The P. falciparum genome encodes 10 aspartic proteases called plasmepsins, which are involved in diverse cellular processes. Most have been studied extensively but the functions of plasmepsins IX and X (PMIX and PMX) were unknown. Here we show that PMIX is essential for erythrocyte invasion, act...