CCNA2
Description
The CCNA2 (cyclin A2) is a protein-coding gene located on chromosome 4.
CCNA2 is a gene encoding a protein known as Cyclin-A2. It is one of two cyclin A proteins, with Cyclin A1 expressed during meiosis and embryogenesis, while Cyclin A2 is expressed in the mitotic division of somatic cells. CCNA2, like other cyclins, regulates cell cycle progression by associating with CDK kinases. It uniquely activates two different CDK kinases: CDK2 during S phase and CDK1 during the G2-to-M transition. Synthesized at the onset of S phase, CCNA2 localizes to the nucleus, where the CCNA2-CDK2 complex is involved in initiating and progressing DNA synthesis. The complex's phosphorylation of CDC6 and MCM4 prevents DNA re-replication during the cell cycle. CCNA2 participates in the G2/M transition but cannot form a maturation promoting factor (MPF) independently. Recent studies have shown that the CCNA2-CDK1 complex triggers cyclin B1-CDK1 activation, leading to chromatin condensation and nuclear envelope breakdown. CCNA2 levels are tightly synchronized with cell cycle progression. Transcription initiates in late G1, peaks and plateaus in mid-S, and declines in G2.
CCNA2 is a cyclin that plays a crucial role in regulating the cell cycle's G1/S and G2/M transition phases. It achieves this by forming distinct serine/threonine protein kinase holoenzyme complexes with the cyclin-dependent protein kinases CDK1 or CDK2. The cyclin subunit of CCNA2 dictates the substrate specificity of these complexes and dynamically interacts with and activates CDK1 and CDK2 throughout the cell cycle.
CCNA2 is also known as CCN1, CCNA.
