This project aims at delineating the regulatory signaling processes that enable cells to overcome DNA damage during DNA replication, a major challenge to the integrity of the genome as the normal replication machinery is unable to replicate past DNA lesions. This may result in collapse of the replication fork, potentially giving rise to gross genomic alterations. To mitigate this threat, all cells have evolved DNA damage bypass strategies such as translesion DNA synthesis (TLS), involving low fidelity DNA polymerases that can replicate damaged DNA, albeit in an error-prone manner, offering a trade-off between limited mutagenesis and gross chromosomal instability. How DNA damage bypass pathways are regulated and integrated with DNA replication and repair remain poorly resolved questions fundamental to understanding genome stability maintenance and disease onset. Regulatory signaling mediated by the small modifier protein ubiquitin has a prominent role in orchestrating the reorganization of the replication fork necessary for overcoming DNA lesions, but this involvement has not been systematically explored. To remedy these gaps in our knowledge, I propose to implement a series of innovative complementary strategies to isolate and identify the regulatory factors and ubiquitin-dependent processes that promote DNA damage responses at the replication fork, allowing for subsequent in-depth characterization of their roles in protecting genome integrity by targeted functional studies. This project will enable an advanced level of mechanistic insight into key regulatory processes underlying replication-associated DNA damage responses that has not been feasible to achieve with exisiting methodologies, providing a realistic outlook for groundbreaking discoveries that will open up many new avenues for further research into mechanisms and biological functions of regulatory signaling processes in the DNA damage response and beyond.