The Mitotic Exit Network: new turns on old pathways

• Mitotic exit in budding yeast is controlled by the MEN.
• We discuss the functions of the MEN in various organisms throughout the cell cycle.
• We suggest models for how early and late MEN roles are coordinated in time and space.
• We propose a dynamic model for mitotic exit.

In budding yeast, the Mitotic Exit Network (MEN) is a signaling pathway known to drive cells out of mitosis and promote the faithful division of cells. The MEN triggers inactivation of cyclin-dependent kinase (Cdk1), the master regulator of mitosis, and the onset of cytokinesis after segregation of the daughter nuclei. The current model of the MEN suggests that MEN activity is restricted to late anaphase and coordinated with proper alignment of the spindle pole bodies (SPBs) with the division axis. However, recent evidence suggests that MEN activity may function earlier in mitosis, prompting re-evaluation of the current model. Here we attempt to integrate this recent progress into the current view of mitotic exit.