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A cell during anaphase. Microtubules are visible in green. Stages of late M phase in a vertebrate cell. Anaphase (from Ancient Greek ἀνα-() 'back, backward' and φάσις (phásis) 'appearance') is the stage of mitosis after the process of metaphase, when replicated chromosomes are split and the newly-copied chromosomes (daughter chromatids) are moved to opposite poles of the cell.
The cell division cycle protein 20 homolog is an essential regulator of cell division that is encoded by the CDC20 gene [5] [6] in humans. To the best of current knowledge its most important function is to activate the anaphase promoting complex (APC/C), a large 11-13 subunit complex that initiates chromatid separation and entrance into anaphase.
The rapid surge in cyclin B-Cdk1 activity is necessary, as M phase initiation is an all-or-nothing event engaging in hysteresis. Hysteresis of Cdk1 activity via cyclin B drives M phase entry by establishing a minimum threshold of cyclin B concentration.
Anaphase is a very short stage of the cell cycle and it occurs after the chromosomes align at the mitotic plate. Kinetochores emit anaphase-inhibition signals until their attachment to the mitotic spindle. Once the final chromosome is properly aligned and attached the final signal dissipates and triggers the abrupt shift to anaphase. [26]
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
During anaphase A, the cohesins that bind sister chromatids together are cleaved, forming two identical daughter chromosomes. [52] Shortening of the kinetochore microtubules pulls the newly formed daughter chromosomes to opposite ends of the cell. During anaphase B, polar microtubules push against each other, causing the cell to elongate. [53]
After checkpoint deactivation and during the normal anaphase of the cell cycle, the anaphase promoting complex is activated through decreasing MCC activity. When this happens the enzyme complex polyubiquitinates the anaphase inhibitor securin. The ubiquitination and destruction of securin at the end of metaphase releases the active protease ...
MPF is disassembled when anaphase-promoting complex (APC) polyubiquitinates cyclin B, marking it for degradation in a negative feedback loop. In intact cells, cyclin degradation begins shortly after the onset of anaphase (late anaphase), the period of mitosis when sister chromatids are separated and pulled toward opposite spindle poles.