Xeroderma pigmentosum group A-complementing protein (XPA) interacts with nucleotide excision repair (NER) subunits, such as replication protein A (RPA), excision repair complementing 1 protein (ERCC1), and transcription factor II (TFIIH). However, it is widely accepted th at the Xeroderma pigmentosum group C-complementing protein (XPC)-human Rad23 homolog (hHR23B) complex recognizes the DNA damage-induced helical distortion. After this, the transcription factor IIH (TFIIH), XPA (possibly in its homodimeric form), and replication protein A (RPA) arrive sequentially at the site of damage. XPA interacts directly with DNA via the zinc finger motif. RPA coordinates with XPA in the positioning in the nucleotide excision repair (NER) bubble. Defects in the excision repair leads to photosensitivity syndrome called xeroderma pigmentosum (XP).
