Functional Characterization of the Thrombospondin-Related Paralogous Proteins Rhoptry Discharge Factors 1 and 2 Unveils Phenotypic Plasticity in Rhoptry Exocytosis.

To gain access to the intracellular cytoplasmic niche essential for their growth and replication, apicomplexan parasites such as rely on the timely secretion of two types of apical organelles named micronemes and rhoptries. Rhoptry proteins are key to host cell invasion and remodeling, however, the molecular mechanisms underlying the tight control of rhoptry discharge are poorly understood. Here, we report the identification and functional characterization of two novel thrombospondin-related proteins implicated in rhoptry exocytosis.