Figure 4. The figure shows the various interactions of DNMT1. DNMT1 participates in a number of collaborations with a host of regulatory proteins and nuclear re-programmers that simultaneously affect DNMT1 activity as well as its functional exchange. DNMT1 works in concert with proteins found at DNA replication forks—PCNA, proteins participating in chromatin re-organization—DNA methyltransferase DNMT3A and DNMT3B, HDAC1, HDAC2, DNA binding proteins—MeCp2, MBD2, MBD3 and other chromatin binding proteins—UHRF1 and polycomb proteins, proteins associated with cell cycle regulation or response to DNA damage and tumor suppressors—p21 (WAF), Rb protein, p53 protein, PARP1—and, finally, a number of transcription factors and regulators involved in DNA methylation inheritance.