Fig. 1.

Examination of TgArk1 localization during tachyzoite replication, and its ability to inhibit parasite growth when expressed in a controlled manner as a dead kinase in the presence of Shield-1. a Western blot analysis performed on HA₃-TgArk1, and RH-Δku80 wild-type parasite lysates probed with an anti-HA antibody. HA₃-TgArk1 is found at the expected molecular masses (62 kDa). SAG1 was used as loading control. b Immunofluorescence images reveal that TgArk1 can switch from nucleus to cytoplasm depending on phase during parasite division. Parasites were co-stained with antibodies for HA₃-TgArk1 and IMC1 as well as stained with DAPI. Representative images at two cell cycle phases are shown as identified by established cell cycle criteria based on the absence or presence of internal daughters (red = IMC1). Scale bars represent 2 μm. c Controlled expression of the series of TgArk1 kinase by Shld-1. Western blot analysis of parasites grown in the presence and absence of Shld-1 for 12 h using anti-myc antibodies. SAG1 was used as loading control. d Expression of DD-Myc-TgArk1D/A dead-kinase but not DD-Myc-TgArk1 wild type affects parasite growth. Plaque assays were performed on parasite strains expressing DD-Myc-TgArk1WT or DD-Myc-TgArk1D/A. HFF monolayers were infected with parasites in the presence or absence of Shld-1, fixed after 7 days, and stained with Giemsa