Toxoplasma proteins GRA17 and GRA23 mediate the movement of small molecules between the host and the parasitophorous vacuole.

Purpose: Two secreted Toxoplasma proteins (GRA17 and GRA23) mediate the passage of small molecules between the host cytoplasm and the parasite-containing vacuole. This provides the first molecular explanation to how intracellular, vacuole-residing parasites in the phylum Apicomplexa, like Plasmodium, gain access to host nutrients. Methods: Mouse-derived Bone Marrow Macrophages were infected with Toxoplasma tachyzoites of either WT, dGRA17, dGRA23, or dGRA17rescue genetic background for 4 hours. Results: GRA23 gene expression levels are elevated in the dGRA17 strain but not vice versa. Conclusions: GRA17 and GRA23 are synergistically required for permeability of small molecules into the Toxoplasma parasitophorous vacuole. Toxoplasma and Mouse gene expression profiles from BMDMs infected with either WT (control), dGRA17, gGRA23, or dGRA17rescue (control) tachyzoites were obtained by RNA-Seq on an Illumina HiSeq2000 instruments at 4 hours post-infection.