CDT1/DUP
Developmental stage
Present during G1 and early S phase of the cell cycle. Degraded during the late S, G2, and M phases.
Domain
The PIP-box K+4 motif mediates both the interaction with PCNA and the recruitment of the DCX(DTL) complex: while the PIP-box interacts with PCNA, the presence of the K+4 submotif, recruits the DCX(DTL) complex, leading to its ubiquitination.
Function
Required for both DNA replication and mitosis. DNA replication licensing factor, required for pre-replication complex assembly. Cooperates with CDC6 and the origin recognition complex (ORC) during G1 phase of the cell cycle to promote the loading of the mini-chromosome maintenance (MCM) complex onto DNA to generate pre-replication complexes (pre-RC). Required also for mitosis by promoting stable kinetochore-microtubule attachments (By similarity). Potential oncogene (PubMed:11850834).
Post-translational modifications
Two independent E3 ubiquitin ligase complexes, SCF(SKP2) and the DCX(DTL) complex, mediated CDT1 degradation in S phase. Ubiquitinated by the DCX(DTL) complex, in response to DNA damage, leading to its degradation. Ubiquitination by the DCX(DTL) complex is necessary to ensure proper cell cycle regulation and is PCNA-dependent: interacts with PCNA via its PIP-box, while the presence of the containing the 'K+4' motif in the PIP box, recruit the DCX(DTL) complex, leading to its degradation. Phosphorylation at Thr-28 by CDK2 targets CDT1 for ubiquitynation by SCF(SKP2) E3 ubiquitin ligase and subsequent degradation. The interaction with GMNN protects it against ubiquitination. Deubiquitinated by USP37.
Phosphorylation by cyclin A-dependent kinases at Thr-28 targets CDT1 for ubiquitynation by SCF(SKP2) E3 ubiquitin ligase and subsequent degradation. Phosphorylated at Thr-28 by MAPK8/JNK1, which blocks replication licensing in response to stress. Binding to GMNN is not affected by phosphorylation (PubMed:14993212).
Sequence Similarities
Belongs to the Cdt1 family.
Cellular localization
- Nucleus
- Chromosome
- Centromere
- Kinetochore
- Transiently localizes to kinetochores during prometaphase and metaphase.
Alternative names
Ris2, DNA replication factor Cdt1, Double parked homolog, Retroviral insertion site 2 protein, DUP