Component of the origin recognition complex (ORC) that binds origins of replication. DNA-binding is ATP-dependent. The DNA sequences that define origins of replication have not been identified yet. ORC is required to assemble the pre-replication complex necessary to initiate DNA replication. Component of ORC, a complex composed of at least 6 subunits: ORC1, ORC2, ORC3, ORC4, ORC5 and ORC6. ORC is regulated in a cell-cycle dependent manner. It is sequentially assembled at the exit from anaphase of mitosis and disassembled as cells enter S phase. Interacts with CDC6 and KAT7/HBO1. Interacts with LRWD1 predominantly during the G1 phase and with less affinity during mitosis, when phosphorylated. Expression is cell-cycle regulated, it starts to accumulate in mid-G1 phase, reaches a peak at the G1/S boundary, and decreases to a basal level in S phase (at protein level). The BAH domain mediates binding to dimethylated histone H4 'Lys-20' (H4K20me2), which is enriched at replication origins. Phosphorylated during mitosis. The disease is caused by variants affecting the gene represented in this entry. Belongs to the ORC1 family.