B-family polymerases, DNA primase, Dna2 helicase-nuclease, BER/NER enzymes such as MUTYH, NTHL1, and XPD, all coordinate a [4Fe4S] cluster cofactor. Several of these proteins have been demonstrated to participate in DNA-mediated redox signaling; characterization of their redox roles is ongoing. (Below) Under oxidative stress conditions, polymerase δ may be converted to the [4Fe4S]3+ state as a means to stall synthesis under poor cellular conditions. Polymerase δ can be reversibly oxidized and reduced through DNA CT, which may regulate polymerase activity on the lagging strand.