Question

Explain how the progression of cells past sequential cell cycle checkpoints and the activity of enzymes such as separase is controlled by interactions between two major groups of regulatory proteins

Answer 1

Answer:

In multicellular organisms, which begin their life with an egg or zygote cell, mitotic cell division is important in the development and maintenance of the various tissues, organs and systems that form it. The new cells caused by mitosis are genetically identical to the stem cell; This is achieved thanks to complex regulatory mechanisms that ensure the integrity of the genomic material and its proper segregation.

Explanation:

Segurine is important because it is responsible for keeping sequestered protease separase; when it is released, thanks to the degradation of segurin, the degradation of the cohesin that holds the sister chromatids together takes place. This cohesin allows chromosomal segregation, while degradation of cyclin results in the inactivation of CDK1 (cyclin dependent kinase).

When the alignment of the chromosomes does not satisfy the SAC (spindle assembly control point), the signal from non-anchored kinetocores induces protein recruitment to the control point. This signal leads to the formation of two independent complexes. The union of the two complexes will lead to the formation of a mitotic control complex. In this way, the segurin will not be marked for degradation and the separase will not be released and the chromosomes will not secrete until the requirements of the SAC are met.