Is an ortholog of human SLX1A (SLX1 homolog A, structure-specific endonuclease subunit). Exhibits enzyme binding activity. Contributes to 3'-flap endonuclease activity\; 5'-flap endonuclease activity\; and crossover junction endodeoxyribonuclease activity. Is involved in several processes, including DNA metabolic process\; embryo development\; and larval development. Localizes to the Slx1-Slx4 complex.