Prolonged mitosis: A key indicator for detecting stressed and damaged cells.

During mitosis, chromosomes condense, align to form a metaphase plate and segregate to the two daughter cells. Mitosis is one of the most complex recurring transformations in the life of a cell and requires a high degree of reliability to ensure the error-free transmission of genetic information to the next cell generation. An abnormally prolonged mitosis indicates potential defects that compromise genomic integrity. The mitotic stopwatch pathway detects even moderately prolonged mitoses by integrating memories of mitotic durations, ultimately leading to p53-mediated cell cycle arrest or death. This mechanism competes with mitogen signaling to stop the proliferation of damaged and potentially dangerous cells at a pre-oncogenic stage. Mitosis is a highly vulnerable phase, which is affected by multiple types of cellular damages and diverse stresses. We discuss the hypothesis that the duration of mitosis serves as an indicator of cell health.