I ntracellular parasitism defines the most intimate of interactions between a pathogen and host. Inherent in this equation are the needs of the pathogen to enter the cell and establish a replication-permissive niche while neutralizing and subverting cellular defenses. The protozoan parasite Toxoplasma gondii is particularly adept at every stage of intracellular parasitism, which has contributed...

Long after their discovery, the function and biogenesis of rhoptries remain enigmatic. In Apicomplexan parasites, these organelles discharge and their contents are exocytosed at the time of host cell invasion, and are thus proposed to play an essential role in establishing the parasitophorous vacuole. In Toxoplasma gondii, ROP2 is suspected to serve as the molecular link between host cell mitoc...

he intracellular parasite Toxoplasma gondii hides out in a specialized compartment surrounded by the parasitophorous vacuole membrane (PVM). The PVM associates with host cell organelles, possibly as a way of scavenging lipids from the host cell. On page 95, Sinai and Joiner describe a protein that mediates this association. The new work illuminates a poorly understood aspect of parasite biology...

Serine/threonine kinases secreted from rhoptry organelles constitute important virulence factors of Toxoplasma gondii. Rhoptry kinases are highly divergent and their structures and regulatory mechanism are hitherto unknown. Here, we report the X-ray crystal structures of two related pseudokinases named ROP2 and ROP8, which differ primarily in their substrate-binding site. ROP kinases contain a ...

Plant Rho family GTPases (ROPs) have been investigated primarily for their functions in polarized cell growth. We previously showed that the maize (Zea mays) Leu-rich repeat receptor-like protein PANGLOSS1 (PAN1) promotes the polarization of asymmetric subsidiary mother cell (SMC) divisions during stomatal development. Here, we show that maize Type I ROPs 2 and 9 function together with PAN1 in ...