Cyclins E1 and E2 localise to unique foci, and have distinct subcellular distribution. A. Confocal images of T-47D breast cancer cells immunoprobed with cyclin E1 (red) or cyclin E2 (green), and counterstained with ToPro3 (blue, nuclei). Inset at higher magnification. Scale bars = 5 μm. Experiments are performed in triplicate. Similar data obtained in MCF-7 cells are shown in Additional file 1. B. T-47D cells were lysed to extract total cell proteins (lane 1), total nuclear (lane 2) and total cytoplasmic (lane 3) lysates. In parallel, cell lysates were purified to extract soluble cytoplasmic proteins, soluble nuclear proteins, and chromatin bound proteins. PAGE separated proteins were western blotted for Cdc6 (predominantly chromatin bound), CDK2 (cytoplasmic, nuclear and chromatin bound), cyclin E1 and cyclin E2. C. Cyclins E1 and E2 were quantitated from duplicate experiments using densitometry (ImageJ), and soluble cytoplasmic, soluble nuclear, and chromatin-bound fractions graphed as a percentage of total extracted protein. Error bars show range.