Figure 1. The K898E mutation disrupts binding between BRCA1 and PP1α.

(a) GST pull-down assay. GST-BF4 proteins (WT and K898E) were employed to determine their interactions with recPP1α. Coomassie Blue staining indicates that approximately equal amounts of GST-BF4 fusion proteins were used. (b) Coimmunoprecipitation. The amount of PP1αmyc coimmunoprecipitated with GFPBRCA1 K898E was 0.38 ± 0.11 of that coimmunoprecipitated with WT GFPBRCA1 (mean ± SEM of two independent experiments, P < 0.03). Gels were run in similar conditions. The full- length immunoblots are shown in Supplementary Information section (Supplementary Fig. S2a and b online).