Factor involved in transcription-coupled nucleotide excision repair (TC-NER), a mechanism that rapidly removes RNA polymerase II-blocking lesions from the transcribed strand of active genes ( ). Facilitates the ubiquitination of the elongating form of RNA polymerase II (RNA pol IIo) at DNA damage sites, thereby promoting RNA pol IIo backtracking and access by the TC-NER machinery to lesion sites (, ). Acts by promoting stabilization of ERCC6 by recruiting deubiquitinating enzyme USP7 to TC-NER complexes, preventing UV-induced degradation of ERCC6 by the proteasome (, ). Also facilitates transfer of TFIIH to RNA polymerase II . Not involved in processing oxidative damage .
Subcellular locations: Chromosome
Accumulates at UV DNA damage sites.