Involved in DNA nucleotide excision repair (NER). 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 (PubMed:19197159). During NER stimulates the 5'-3' helicase activity of XPD/ERCC2 and the DNA translocase activity of XPB/ERCC3 (PubMed:31253769). Connects XPD/ERCC2 and XPB/ERCC3 during NER, retaining DNA near the XPB/ERCC3 active site, and stabilizing the complex in a different conformation than in transcribing TFIIH (PubMed:31253769). {ECO:0000269|PubMed:19197159, ECO:0000269|PubMed:31253769}. This is the function of XPA (XPA, DNA damage recognition and repair factor, Ensembl gene identifier ENSG00000136936).