Interplay of DNA damage and cell cycle signaling at the level of human replication protein A

- RPA in S and G2 phases shows complex regulation by phosphorylation.
- Control cell lysates have 5 RPA heterotrimer isoforms with up to 7 phosphates.
- DNA damaged lysates show 9 RPA isoforms having up to 14 phosphates.
- DNA damage isoforms in S and G2 contain RPA2 pS4/8, pS12, pT21, pS23, and pS33.
- Six other PIKK sites on RPA1 and RPA2 may be involved in the DDR.