Interfering with TgArk1 function increasingly affects the duplication of the centrosome outer core and impairs its clustering with the centrosome inner core. a Co-staining of TgCentrin1 (a centrosome outer core marker, red dots) and TgCEP250L1-HA3 (a centrosome inner core marker, green dots) shows their over-duplication and under-duplication, respectively, and their detachment (red arrows) in the ark1D/A-Δku80 strain treated with shield-1 (lower panel). The ark1D/A-Δku80 strain in absence of shield-1 (top panel) shows a normal pairing of both centrosome cores per nucleus (one centrosome outer core clusters/one centrosome inner core; two cen- trosome outer core clusters/two centrosome inner cores). The nuclei are stained with DAPI (in blue). Scale bars represent 2 μm. b The average of TgCentrin1 containing centrosome outer cores per parasite, was quantified in 900 parasites revealing a significant amplification of the centrosome outer core when ark1D/A-Δku80 parasites were treated in presence of shield-1 (red dots). Values are mean ± SD for three independent experiments. c Co-staining of TgCentrin1 (a centrosome outer core marker, green dots) and TgNDC80 (a kinetochore marker, red dots) shows their over-duplication and underduplication, respectively, and their detachment (red arrows) in the ark1D/A-Δku80 strain treated with shield-1 (lower panel). The ark1D/A-Δku80 strain in absence of shield-1 (top panel) shows a normal pairing of centrosome outer core/kinetochore per nucleus (two centrosome outer core clusters/one kinetochore; two centrosome outer core clusters/two kinetochores). The nuclei are stained with DAPI (in blue). Scale bars represent 2 μm. d Quantification of the number of parasites showing clustered or detached centrosome outer core/ kinetochore pairing in three different strains (RH-Δku80, ark1WT- Δ-Δ80 and ark1D/A-Δku80) in the presence or absence of shield-1 for 12 h. At least 900 parasites were examined for each condition. Values are mean ± SD for three independent experiments. e Co-staining of TgCentrin1 (a centrosome outer core marker, red dots) and TgChromo1-HA3 (a centromere marker, green dots) shows their overduplication and under-duplication, respectively, and their detachment (red arrows) in the ark1D/A-Δku80 strain treated with shield-1 (lower panel). The ark1D/A-Δku80 strain in the absence of shield-1 (top panels) shows a normal pairing of centrosome outer core/centromere per nucleus (two centrosome outer core clusters/one centromere; two centrosome outer core clusters/two centromeres). The nuclei are stained with DAPI (in blue). Scale bars represent 2 μm