Substrate recognition component of a DCX (DDB1-CUL4-X-box) E3 protein ligase complex that mediates the ubiquitination and subsequent proteasomal degradation of target proteins, such as MEIS2 (Probable). Normal degradation of key regulatory proteins is required for normal limb outgrowth and expression of the fibroblast growth factor FGF8. Maintains presynaptic glutamate release and consequently cognitive functions, such as memory and learning, by negatively regulating large-conductance calcium-activated potassium (BK) channels in excitatory neurons. Likely to function by regulating the assembly and neuronal surface expression of BK channels via its interaction with KCNT1 (By similarity). May also be involved in regulating anxiety-like behaviors via a BK channel-independent mechanism (By similarity). Protein modification; protein ubiquitination. Component of a DCX (DDB1-CUL4-X-box) protein ligase complex. Belongs to the CRBN family.