PIAS3 promotes homology-directed repair and distal non-homologous end joining

A DNA double-strand break (DSB) is the most severe form of DNA damage and is mainly repaired through homologous recombination (HR), which has a high fidelity, or non-homologous end joining (NHEJ), which is prone to errors. Defects in the DNA damage response lead to genomic instability and ultimately the predisposition of organs to cancer. Protein inhibitor of activated STAT-1 (PIAS1), which is a potential small ubiquitin-related modifier (SUMO) ligase, has been reported to be involved in DSB repair. The present study identified that another member of the PIAS family, PIAS3, is also an enhancer for HR- and NHEJ-mediated DSB repair. Furthermore, the overexpression of PIAS3 was demonstrated to increase the resistance of HeLa cells to ionizing radiation (IR), indicating a significant role for PIAS3 in the DNA damage response (DDR) pathway.