APC10-like DOC1 domain present in HERC2 (HECT domain and RLD2).
This model represents the APC10/DOC1 domain present in HERC2 (HECT domain and RLD2), a large multi-domain protein with three RCC1-like domains (RLDs), additional internal domains including a zinc finger ZZ-type and Cyt-b5 (Cytochrome b5-like Heme/Steroid binding) domains, and a C-terminal HECT (Homologous to the E6-AP Carboxyl Terminus) domain. The APC10/DOC1 domain of HERC2 is a homolog of the APC10 subunit and the DOC1 domain present in E3 ubiquitin ligases which mediate substrate ubiquitination (or ubiquitylation), a component of the ubiquitin-26S proteasome pathway for selective proteolytic degradation. As suggested by structural relationships between HERC2 and other proteins such as HERC1, the proposed role for HERC2 in protein trafficking and degradation pathways is consistent with observations that mutations in HERC2 lead to neuromuscular secretory vesicle and sperm acrosome defects, other developmental abnormalities, and juvenile lethality of jdf2 mice. Recent studies have shown that the protein complex, HERC2-RNF8, coordinates ubiquitin-dependent assembly of DNA repair factors on damaged chromosomes.