APC10 subunit of the anaphase-promoting complex (APC) that mediates substrate ubiquitination.
This model represents the single domain protein APC10, a subunit of the anaphase-promoting complex (APC), which is a multi-subunit E3 ubiquitin ligase. E3 ubiquitin ligases mediate substrate ubiquitination (or ubiquitylation), a vital component of the ubiquitin-26S proteasome pathway for selective proteolytic degradation. The APC (also known as the cyclosome), is a cell cycle-regulated E3 ubiquitin ligase that controls important transitions in mitosis and the G1 phase by ubiquitinating regulatory proteins, thereby targeting them for degradation. In mitosis, the APC initiates sister chromatid separation by ubiquitinating the anaphase inhibitor securin and triggers exit from mitosis by ubiquitinating cyclin B. The C-terminus of APC10 binds to CDC27/APC3, an APC subunit that contains multiple tetratrico peptide repeats. APC10 domains are homologous to the DOC1 domains present in the HECT (Homologous to the E6-AP Carboxyl Terminus) E3 ubiquitin ligase protein, and the Cullin-RING (Really Interesting New Gene) E3 ubiquitin ligase complex. The APC10/DOC1 domain forms a beta-sandwich structure that is related in architecture to the galactose-binding domain-like fold; their sequences are quite dissimilar, however, and are not included here.