CUL4 associates with DDB1 and DET1 and its downregulation affects diverse aspects of development in Arabidopsis thaliana.

Cullins are central scaffolding subunits in eukaryotic E3 ligases that facilitate the ubiquitination of target proteins. Arabidopsis contains at least 11 cullin proteins but only a few of them have been assigned biological roles. In this work Arabidopsis cullin 4 is shown to assemble with DDB1, RBX1, DET1 and DDB2 in vitro and in planta.

Arabidopsis AtCUL3a and AtCUL3b form complexes with members of the BTB/POZ-MATH protein family.

The ubiquitin proteasome pathway in plants has been shown to be important for many developmental processes. The E3 ubiquitin-protein ligases facilitate transfer of the ubiquitin moiety to substrate proteins. Many E3 ligases contain cullin proteins as core subunits.