Substrate-recognition component of a DCX (DDB1-CUL4-X-box) E3 ubiquitin-protein ligase complex of the DesCEND (destruction via C-end degrons) pathway, which recognizes a C-degron located at the extreme C terminus of target proteins, leading to their ubiquitination and degradation. The C-degron recognized by the DesCEND pathway is usually a motif of less than ten residues and can be present in full-length proteins, truncated proteins or proteolytically cleaved forms. The DCX(DCAF12) complex specifically recognizes proteins with a diglutamate (Glu-Glu) at the C-terminus, leading to their ubiquitination and degradation. Protein modification; protein ubiquitination. Component of the DCX(DCAF12) E3 ubiquitin ligase complex, at least composed of CUL4 (CUL4A or CUL4B), DDB1, DCAF12 and RBX1. Belongs to the WD repeat DCAF12 family.