Catalyzes 3'-non-homologous tail removal of RAD1/RAD10-dependent single-strand annealing recombination intermediates. Plays a key role in targeting RAD1/RAD10 complex to 3'-flap cleavage substrate in recombination. Also contributes to the integrity of ribosomal DNA arrays. Interacts with MSH2, MSH3, RAD1, RAD10, RAD51 and RAD52. Accumulates recombination intermediates blocked at the RAD1/RAD10-dependent 3' flap cleavage step. Abolishes association of RAD1 at single-strand annealing (SSA) intermediates. Insensitive to MMS, HU, or phleomycin treatment. Doesn't sensitize cells to UV lesions. Substantially increases the rDNA recombination rate. Present with 1170 molecules/cell in log phase SD medium.