DCUN1D1 (DCUN1 domain-containing protein 1) contains a DUF298 domain and a UBA-like ubiquitin. Forms part of an E3 ubiquitin ligase complex for neddylation. Required for neddylation of cullin components of E3 cullin-RING ubiquitin ligase complexes by enhancing the rate of cullins neddylation. Functions to recruit the NEDD8-charged E2 enzyme to the cullin component. Involved in the release of inhibitory effets of CAND1 on cullin-RING ligase E3 complex assembly and activity. Acts also as an oncogene facilitating malignant transformation and carcinogenic progression. Defects in DCUN1D1 may be a cause of squamous cell carcinomas. Strongly overexpressed in thyroid tumors, bronchioloalveolar carcinomas, and malignant tissues of squamous cell carcinoma of the oral tongue. Not overexpressed in aggressive adrenocortical carcinomas.