Role in The Spindle Assembly Checkpoint
The spindle assembly checkpoint inhibits progression of mitosis from metaphase to anaphase until all sister chromatid pairs are bioriented. Cells lacking Aurora B fail to arrest in metaphase even when chromosomes lack microtubule attachment. Consequently, Aurora B deficiency leads to progression through anaphase despite the presence of misaligned chromosomes.
Aurora B may be involved in the localization of MAD2 and BubR1, proteins that recognize correct chromosome attachment to spindle microtubules. Loss of Aurora B lowers the concentration of Mad2 and BubR1 at the kinetochores. In particular, Aurora B seems to be responsible for maintaining the localization of Mad2 and BubR1 to the kinetochore following their initial recruitment, which occurs independent of Aurora B. Aurora B may be directly or indirectly involved in the hyper-phosphorylation of BubR1 seen in mitosis in wild-type cells.
Read more about this topic: Aurora B Kinase
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