Figure 3.

PLK1-dependent degradation of NOTCH1 at the G₂-M transition. A and B, HaCaT and SCCO22 cells were collected at the indicated time points after release from G₁/S, cell cycle was analyzed by FACS (FACS profile is shown only for HaCaT cells), and cell lysates were immunoblotted with antibodies to the indicated proteins. C, HaCaT cells were treated for 16 h with nocodazole to induce a mitotic block, and BI2536 (PLK1 inhibitor) was added 8 h before harvesting. Prometaphase cells were then collected by shake-off, and cell extracts were analyzed by immunoblotting with antibodies to the indicated proteins. Shown are representative results from at least three independent experiments. NOC, nocodazole; HU, hydroxyurea.