SILAC and label-free pull-downs of CDC23. (A) SILAC pull-down of CDC23 versus the untagged HeLa cell line. Annotated proteins were specific interaction partners of CDC23 with a p-value of ratio significance <0.001. APC core proteins are separated from APC adaptors (CDC20 and FZR1) by intensity. (B) Volcano plot representing results of the label-free pull-down of CDC23. The logarithmic ratio of protein intensities in the CDC23/HeLa pull-downs were plotted against negative logarithmic p-values of the t test performed from triplicates. A hyperbolic curve separates specific CDC23-interacting proteins marked in black (red dotted line) from background (blue dots). The known components of the APC (C10orf104/ANAPC16 only recently characterized in parallel studies), several known APC adaptors, and one uncharacterized protein, C11orf51, show a significant ratio in combination with high reproducibility (positive log2 ratios). (C) Localization patterns of GFP-tagged CDC23 and the new component C11orf51 in interphase. Bars, 10 µm.