XPC: its product and biological roles.

The XPC protein is a component of a heterotrimeric complex that is essential for damage recognition in a nucleotide excision repair subpathway that operates throughout the genome. Biochemical analyses have revealed that the broad substrate specificity of this repair system is based on the structure-specific DNA binding properties of the XPC complex. Other subunits of this complex, including human Rad23p orthologs and centrin 2, play individual roles in enhancing the damage recognition activity of XPC. Physical interaction with UV-damaged DNA-binding protein is also important for the efficient recruitment of XPC to sites containing DNA damage, particularly UV-induced photolesions. Furthermore, recent studies have suggested that XPC may also be involved in base excision repair and possibly in other cellular functions that may be mediated by posttranslational modifications.