Involved in nucleotide excision repair (NER). Functional in repair of ultraviolet radiation induced damages and in mitotic mutation avoidance. Binds damaged DNA. Binds specifically to base-base mismatches or small insertion/deletion loops with unpaired nucleotides. Maintains GT repeat stability. Functions as a part of the short-patch excision repair system. Interacts with hrq1. Belongs to the XPA family.