Involved in DNA excision repair. Initiates repair by binding to damaged sites with various affinities, depending on the photoproduct and the transcriptional state of the region. Required for UV-induced CHEK1 phosphorylation and the recruitment of CEP164 to cyclobutane pyrimidine dimmers (CPD), sites of DNA damage after UV irradiation (By similarity). Interacts with GPN1. Interacts with RPA1 and RPA2; the interaction is direct and associates XPA with the RPA complex. Interacts (via N-terminus) with CEP164 upon UV irradiation. Interacts with HERC2 (By similarity). Ubiquitinated by HERC2 leading to degradation by the proteasome. Belongs to the XPA family.