Involved in the homologous recombination repair (HRR) pathway of double-stranded DNA, thought to repair chromosomal fragmentation, translocations and deletions. Part of the Rad21 paralog protein complex BCDX2 which acts in the BRCA1-BRCA2-dependent HR pathway. Upon DNA damage, BCDX2 acts downstream of BRCA2 recruitment and upstream of RAD51 recruitment. BCDX2 binds predominantly to the intersection of the four duplex arms of the Holliday junction and to junction of replication forks. The BCDX2 complex was originally reported to bind single-stranded DNA, single-stranded gaps in duplex DNA and specifically to nicks in duplex DNA.JP Scott, Blood, Oct 1981; 58: 665 - 669. G Chevalier, Am. J. Pathol., Jun 1998; 152: 1563. R Williams, J. Biol. Chem., Aug 1993; 268: 18213 - 18217. Michael R. Ladomery, J. Biol. Chem., Dec 1999; 274: 36520.