Eukaryotic Armadillo (ARM) repeat proteins are multifaceted with prominent roles in cell-cell adhesion, cytoskeletal regulation and intracellular signaling among many others. One such ARM repeat containing protein, ARM Repeats Only (ARO), has recently been demonstrated in both Toxoplasma (TgARO) and Plasmodium (PfARO) parasites to be targeted to the rhoptries during the late asexual stages. TgA...

The low-molecular-mass rhoptry complex of Plasmodium falciparum consists of three proteins, rhoptry-associated protein 1 (RAP1), RAP2, and RAP3. The genes encoding RAP1 and RAP2 are known; however, the RAP3 gene has not been identified. In this study we identify the RAP3 gene from the P. falciparum genome database and show that this protein is part of the low-molecular-mass rhoptry complex. Dis...

Members of the phylum Apicomplexa actively enter host cells by a process involving the discharge of the apically localized microneme and rhoptry organelles. To unravel the processes involved in rhoptry organelle biogenesis, we focused on the Toxoplasma gondii armadillo repeats only protein (TgARO), a conserved acylated protein homogenously anchored to the rhoptry membrane. Conditional disruptio...

Tip growth in neuronal cells, plant cells, and fungal hyphae is known to require tip-localized Rho GTPase, calcium, and filamentous actin (F-actin), but how they interact with each other is unclear. The pollen tube is an exciting model to study spatiotemporal regulation of tip growth and F-actin dynamics. An Arabidopsis thaliana Rho family GTPase, ROP1, controls pollen tube growth by regulating...

Nitrogen (N) availability is one of the most important factors regulating plant metabolism and growth as it affects global gene expression profiles. Dynamic changes in chromatin structure, including histone modifications nucleosome assembly/disassembly, have been extensively shown to regulate under various environmental stresses plants. However, involvement related nutrient responses has demons...

Trafficking of the rhoptry chimeric protein RhopH2-GFP, which contains RhopH2 signal peptide plus the downstream five amino acids, was dissected by treating parasites with Brefeldin A at three different time points. Twenty eight hrs-stage trophozoites accumulated the chimera within the parasite endoplasmic reticulum. In 32 hrs-stage schizonts, the chimera was distributed in the parasite cytopla...

UNLABELLED Ingestion of the obligate intracellular protozoan parasite Toxoplasma gondii causes an acute infection that leads to chronic infection of the host. To facilitate the acute phase of the infection, T. gondii manipulates the host response by secreting rhoptry organelle proteins (ROPs) into host cells during its invasion. A few key ROP proteins with signatures of kinases or pseudokinases...

The 235-kDa family of rhoptry proteins in Plasmodium yoelii and the two reticulocyte binding proteins of P. vivax comprise a family of proteins involved in host cell selection and erythrocyte invasion. Here we described a member of the gene family found in P. falciparum (PfRH3) that is transcribed in its entirety, under stage-specific control, with correct splicing of the intron, but appears no...

Rhoptry protein 2 (ROP2) of Toxoplasma gondii is a rhoptry-secreted protein that plays a critical role in parasitophorous vacuole membrane formation during invasion. In previous studies, ROP2 has been shown to be efficient in triggering humoral and cell-mediated responses. High immunogenicity of ROP2 makes it a potential candidate for diagnosis and vaccination against toxoplasmosis. In this stu...