Toward a systems-level view of mitotic checkpoints

TL;DR

This paper reviews the mechanisms and significance of two key mitotic checkpoints, SAC and SPOC, highlighting their roles in ensuring proper cell division and implications for developmental defects and cancer.

Contribution

It provides a comparative overview of SAC and SPOC, emphasizing their conserved functions and potential existence of similar mechanisms in animal cells.

Findings

SAC prevents premature sister chromatid separation.

SPOC ensures correct spindle alignment before mitotic exit.

Disruption of checkpoints can lead to developmental issues or tumors.

Abstract

Reproduction and natural selection are the key elements of life. In order to reproduce, the genetic material must be doubled, separated and placed into two new daughter cells, each containing a complete set of chromosomes and organelles. In mitosis, transition from one process to the next is guided by intricate surveillance mechanisms, known as the mitotic checkpoints. Dis-regulation of cell division through checkpoint malfunction can lead to developmental defects and contribute to the development or progression of tumors. This review approaches two important mitotic checkpoints, the spindle assembly checkpoint (SAC) and the spindle position checkpoint (SPOC). The highly conserved spindle assembly checkpoint (SAC) controls the onset of anaphase by preventing premature segregation of the sister chromatids of the duplicated genome, to the spindle poles. In contrast, the spindle position checkpoint (SPOC), in the budding yeast S. cerevisiae, ensures that during asymmetric cell division mitotic exit does not occur until the spindle is properly aligned with the cell polarity axis. Although there are no known homologs, there is indication that functionally similar checkpoints exist also in animal cells.