Acetylation of cyclin A: a new cell cycle regulatory mechanism.

Cyclin A must be degraded at prometaphase in order to allow mitosis progression. Nevertheless, the signals that trigger cyclin A degradation at mitosis have been largely elusive. In the present paper, we review the status of cyclin A degradation in the light of recent evidence indicating that acetylation plays a role in cyclin A stability. The emerging model proposes that the acetyltransferase PCAF [p300/CREB (cAMP-response-element-binding protein)-binding protein-associated factor] [perhaps also its homologue GCN5 (general control non-derepressible 5)] acetylates cyclin A at Lys(54), Lys(68), Lys(95) and Lys(112) during mitosis, leading to its ubiquitylation by the anaphase-promoting factor/cyclosome and its subsequent degradation via proteasome. Interestingly, these four lysine residues in cyclin A also participate in the regulation of cyclin A-Cdk (cyclin-dependent kinase) activity by modulating its interaction with Cdks.