Substrate-recognition component of the DCX(DCAF15) complex, a cullin-4-RING E3 ubiquitin-protein ligase complex that mediates ubiquitination and degradation of target proteins. The DCX(DCAF15) complex acts as a regulator of the natural killer (NK) cells effector functions. Protein modification; protein ubiquitination. Component of the DCX(DCAF15) complex, also named CLR4(DCAF15) complex.