Role of ubiquitination in the DNA damage response: proteomic analysis to identify new DNA-damage-induced ubiquitinated proteins.

The DDR (DNA damage response) is a signalling transduction cascade utilizing many forms of post-translation modification of proteins, including phosphorylation and ubiquitination. The well-known function of ubiquitination is to target proteins for proteasomal degradation; however, it is also involved in the regulation of protein function. The present review describes how ubiquitination regulates the function of certain proteins involved in DDR, in particular FANCD2 (Fanconi's anaemia complementation group D2) and PCNA (proliferating-cell nuclear antigen). Also, the proteomic methods currently used to identify new ubiquitinated proteins in response to DNA damage, including the advantages of using the UBD (ubiquitin-binding domain) beads to purify the ubiquitinated proteins, are considered.