The primary function of CDT1 is to ensure that DNA replication occurs only once per cell cycle. By facilitating the loading of the MCM complex onto replication origins, CDT1 helps to license the DNA for replication. After the G1 phase, CDT1 is tightly regulated to prevent re-replication, which could lead to genomic instability. This regulation is achieved through various mechanisms, including ubiquitination and proteolysis.
