Figure 2.

Common functional complexes of cyclin E1 and E2. A. Cyclin E1 and E2 both co-immunoprecipitate CDK2/CDK2 inhibitor complexes. Lysates of T-47D cells were immunoprecipitated and then western blotted using the indicated antibodies. Data are representative of duplicate experiments. Similar data from MCF7 cells are shown in [19]. IB: immunoblot; IP: immunoprecipitation B. Cyclin E1 and E2 both co-immunoprecipitate SAP145. Lysates of T-47D cells were immunoprecipitated and then western blotted using the indicated antibodies. Data are representative of triplicate experiments. In A. and B. arrows indicate protein of interest; IgG is non-specific immunoglobulin G staining. C. Cyclins E1 and E2 both co-purify with centrosomes. T-47D cells were arrested and synchronised at G₀ with anti-estrogen ICI 182780 followed by estrogen stimulation for 16h. Lysates were separated by ultracentrifugation on sucrose gradients, fractionated, then pelleted and resuspended in sample buffer for western blotting with the indicated antibodies. γ-tubulin and centrin-2 are centrosome components, and estrogen receptor α (ER) is a non-centrosomal negative control. Data are representative of duplicate experiments. Similar data obtained in MCF-7 cells are shown in Additional file 2.