APC10-like DOC1 domain of CUL7, subunit of the SCF-ROC1-like E3 ubiquitin ligase complex that mediates substrate ubiquitination.
This model represents the APC10/DOC1 domain present in CUL7, a subunit of the SCF-ROC1-like E3 Ubiquitin (Ub) ligase complex, which mediates substrate ubiquitination (or ubiquitylation), and is a component of the ubiquitin-26S proteasome pathway for selective proteolytic degradation. CUL7 is a member of the Cullin-RING ligase family and functions as a molecular scaffold assembling the SCF-ROC1-like E3 Ub ligase complex consisting of the adapter protein Skp1, CUL7, the WD40 repeat-containing F-box Fbw8 (also known as Fbx29), and ROC1 (RING-box protein 1). CUL7 is a large protein with a C-terminal cullin domain that binds ROC1 and additional domains, including an APC10/DOC1 domain. While the Fbw8 protein is responsible for substrate protein recognition, the ROC1 RING domain recruits an Ub-charged E2 Ub-conjugating enzyme for substrate ubiquitination. It remains to be determined how CUL7 binds to the Skp1-Fbw8 heterodimer. The CUL7 E3 Ub ligase has been implicated in the proteasomal degradation of the cellular proteins, cyclin D1, an important regulator of the G1 to S-phase cell cycle progression, and insulin receptor substrate 1, a critical component of the signaling pathways downstream of the insulin and insulin-like growth factor 1 receptor. CUL7 appears to be an important regulator of placental development. Germ line mutations of CUL7 are linked to 3-M syndrome and Yakuts short stature syndrome.