p21Cip1, regulator of fine-tuned mitosis and anti-cancer target

Deregulated cell cycle is a hallmark of tumor development. p21Cip1 is a key player in regulating the cell cycle and has been shown to be a tumor suppressor and an oncogene as well. Its function in the interphase of the cell cycle is well studied and its potential role in mitosis is only anticipated. We show that p21Cip1 is important for a fine-tuned mitotic progression by inhibiting the activity of cyclin-dependent kinase 1 (Cdk1)/cyclin B1, the master kinase of mitosis. Loss of p21Cip1 prolongs the duration of mitosis by arresting cells at metaphase, anaphase and cytokinesis. Time-lapse microscopy experiments a…