Probable substrate recognition component of tsome E3 ubiquitin-protein ligase complex (By similarity). Plays a key role in cell competition via its interaction with l(2)gl. Protein modification; protein ubiquitination. Component of the CUL4-RBX1-DDB1-DCAF1 E3 ubiquitin-protein ligase complex (By similarity). Interacts with l(2)gl. The DWD boxes are required for interaction with DDB1. Homozygous mutants develop more slowly and die at a late pupal stage. Zygotic mutants do not have obvious patterning defects during embryonic or larval development but cells undergo apoptosis when surrounded by wild-type cells in the wing disk epithelium. Belongs to the VPRBP/DCAF1 family.