Ultraviolet light induced pyrimidine dimer is a helix distortion DNA damage type,
which recruits repair complexes. However, proteins of these complexes that take part
in both DNA damage recognition and repair have been well-described, the regulation
of the downstream steps of nucleotide excision repair (NER) have not been clearly
clarified yet. In a high-throughput screen, we identified SerpinB2 (SPB2) as one of
the most dramatically upregulated gene in keratinocytes following UV irradiation.
We found that both the mRNA and the protein levels of SPB2 were increased upon UV
irradiation in various cell lines. Additionally, UV damage induced translocation of
SPB2 from the cytoplasm to the nucleus as well as the damage induced foci formation
of it. Here we show that SPB2 co-localizes with XPB involved in the NER pathway at
UV-induced repair foci. Finally, we demonstrated that UV irradiation promoted the
association of SPB2 with ubiquitylated proteins. In basal cell carcinoma tumour cells,
we identified changes in the subcellular localization of SPB2. Based on our results,
we conclude that SPB2 protein has a novel role in UV-induced NER pathway, since it
regulates the removal of the repair complex from the damaged site leading to cancerous
malformation.
