RAD17 is a checkpoint clamp loader component essential for DNA damage response and genome stability 1. As part of the RAD17-RFC complex, RAD17 possesses weak ATPase activity required for chr5 binding and functions as a key damage sensor protein in the ATR-dependent checkpoint pathway 1. RAD17 loads the 9-1-1 (RAD9-RAD1-HUS1) clamp complex onto dsDNA-ssDNA junctions at sites of DNA damage, with structural specificity for 9-1-1 over PCNA 2. This interaction is regulated by casein kinase 2-dependent phosphorylation of RAD17's C-terminal tail at S667, which promotes 9-1-1 binding and ATR-CHK1 activation 34. RAD17 also mediates recruitment of the MRN complex to DNA damage sites, supporting homologous recombination repair 5. Additionally, RAD17 functions as a replication fork sensor, becoming enriched at stalled forks in a manner that promotes checkpoint activation and fork stabilization 6. Clinically, RAD17 variants have been identified as candidate predisposition factors in families with breast and pancreatic cancer, highlighting its role in cancer prevention 5. Dysregulation of RAD17 splicing contributes to chemoresistance in breast cancer stem cells 7.