Cooperates with CDC6 to promote the loading of the mini- chromosome maintenance complex onto chromatin to form the pre- replication complex necessary to initiate DNA replication. Binds DNA in a sequence-; strand-; and conformation-independent manner. Potential oncogene. {ECO:0000250|UniProtKB:Q8R4E9; ECO:0000269|PubMed:11125146; ECO:0000269|PubMed:14672932; ECO:0000269|PubMed:14993212; ECO:0000269|PubMed:21856198}.