Plk4 kinase activity destabilizes the protein. (A) Schematic of mouse Plk4, showing the location of the kinase domain, the Polo-box domain (PBD), and the cryptic Polo-box domain (Swallow et al., 2005). The locations of the AS and KD mutations are also shown. (B) Immunoblot showing the expression level of WT and KD Plk4-EYFP transgenes. (C) Titration showing the relative expression level of Plk4^WT and Plk4^KD. (D) Immunoblot showing the expression levels of Plk4^WT, Plk4^AS, and Plk4^KD in the presence of DMSO or 1NM-PP1. (E) Immunofluorescence images acquired 48 h after Plk4-EYFP was induced with tetracycline. Cells were grown in DMSO or 1NM-PP1. Insets depict an enlargement of centrioles. Red, SAS-6; green, Plk4-EYFP; blue, DNA. Bars, 10 µm. (F) Graph quantifying of the proportion of cells with more than four centrioles 48 h after expression of Plk4-EYFP was induced. Cells were grown in the presence of either DMSO or 1NM-PP1. Bars represent the mean of at least three independent experiments with >300 cells per condition. Error bars represent the SEM.