cyclin a การใช้

• In late S phase, cyclin A can also associate with CDK1.
• E2F initiates transcription of cyclin A by de-repressing the promoter.
• The structure shows that p27 interacts with both cyclin A and CDK2.
• Degradation of cyclin A / CDK1 induces mitotic exit.
• The phosphorylation at Thr60 is mediated by CK2 and Thr61 is by Cyclin A / Cdk1.
• A study in 2008 provided further evidence of cyclin A / CDK2 complex s role in mitosis.
• Emi1 s destruction leads APC / CCdc20 activation, allowing for the destruction of cyclin A in early mitosis.
• Phosphorylation of E2F turns the transcription factor off, providing another level of controlling the transcription of cyclin A.
• Once cyclin B is activated, cyclin A is no longer needed and is subsequently degraded through the ubiquitin pathway.
• Securin and M Cyclins ( cyclin A and cyclin B ) are then targeted by APC / C Cdc20 for degradation.
• Though how the spindle checkpoint system inhibits cyclin B and securin destruction while allowing cyclin A to be degraded is unknown.
• Cyclin A / CDK2 complex was thought to be restricted to the nucleus and thus exclusively involved in S phase progression.
• Cyclin A is degraded early in mitosis, supporting the theory, but cyclin B and securin are not degraded until metaphase.
• This sequestering then frees up Cyclin A-, E-CDK2 to hyperphosphorylate Rb and promote progression of the cell cycle.
• New research has since debunked this assumption, shedding light on cyclin A / CDK2 migration to the centrosomes in late G 2.
• Skp2 forms a stable complex with the cyclin A-S, G2 phase, and the initial part of the M phase.
• It has also been shown that Cdk2 complexes with both cyclin A and cyclin E and this complex is critical for centrosome duplication.
• Association of cyclin A with CDK2 is required for passage into S phase while association with CDK1 is required for entry into M phase.
• A possible trigger for activation is phosphorylation by cyclin A-Cdk, which functions before cyclin B1-Cdk in the cell cycle.
• In this manner, cyclin A can be degraded while cyclin B and securin are degraded only once sister chromatids have achieved bi-orientation.