maintenance of mitotic sister chromatid cohesion

Definition

Target type: biologicalprocess

The process in which the association between sister chromatids of a replicated chromosome is maintained as chromosomes condense, attach to the spindle in a bipolar orientation, and congress to the metaphase plate during a mitotic cell cycle. [GOC:mah]

The maintenance of mitotic sister chromatid cohesion is a crucial process that ensures the faithful segregation of duplicated chromosomes during cell division. This intricate process involves a multi-protein complex known as cohesin, which physically links sister chromatids together.

Cohesin is loaded onto DNA during DNA replication, forming rings that encircle both sister chromatids. The loading of cohesin is facilitated by the Scc2/Scc4 complex, which acts as a loading factor. Once loaded, cohesin remains bound to DNA throughout S phase and G2 phase, holding the sister chromatids together.

During prophase, the cohesin complex undergoes significant changes to prepare for chromosome segregation. The protein kinase Aurora B, localized to the centromere, phosphorylates the cohesin subunit SA1, weakening the cohesion between sister chromatids. This weakening is particularly important at centromeres, allowing for proper chromosome alignment at the metaphase plate.

As cells enter anaphase, the protease separase, activated by the anaphase promoting complex (APC/C), specifically cleaves the cohesin subunit Scc1, resulting in the complete dissociation of sister chromatids. This cleavage event allows for the separation of chromosomes and their movement to opposite poles of the cell.

The maintenance of mitotic sister chromatid cohesion is tightly regulated, ensuring that chromosomes are correctly replicated and segregated during cell division. Errors in this process can lead to aneuploidy, a condition characterized by an abnormal number of chromosomes, which can result in developmental defects and cancer.'
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Proteins (1)

Compounds (1)