Figure 4. PB3 of PLK4 directly interacts with STIL-CC.
(A) Schematic illustration of PLK4 fragments used to map the STIL-CC binding site. Kinase domain (KD), grey; PB1, yellow; PB2, orange; PB3, blue. The relative strengths of the interactions are indicated (+, strong; -, not detected). (B–D) Western blots of co-immunoprecipitation experiments using HEK293T cells co-transfected with plasmids expressing PLK4 fragments and FLAG-STIL (B) or EGFP-STIL-CC (C and D). Antibodies used for Western blot detection are indicated. (E) Isothermal titration calorimetry of STIL-CC into a solution of PLK4-PB3. Left panel: Direct measurement of the Gibbs energy associated with STIL-CC binding to PLK4-PB3. Right panel: integrated and fitted raw data using a one-site binding model.