BRSK2 protein levels fluctuate during the cell cycle.

(A) HeLa cells were arrested at the G1-S boundary by a double-thymidine block, released into fresh medium, and harvested at the indicated time points. Cell lysates were probed by Western blot (WB) with BRSK2, Aurora B, Cyclin B1, and β-actin antibodies. β-actin served as a loading control. (B) HeLa cells were arrested at prometaphase by a thymidine-nocodazole treatment, released into fresh medium, and harvested at the indicated time points. Cell lysates were probed by Western blot (WB) with BRSK2, Aurora B, p-Histone H3(Ser10), and β-actin antibodies. Cells were treated with MG132 (20 µM) for 8 h during the mitotic exit phase. Cell cycle stages in (A) and (B) were determined by flow cytometry and are indicated in the figure.