The diagram of HECTD3 protein structure. HECTD3 belongs to the other HECT E3s subfamily. It is comprised of a DOC domain and an HECT domain. In the HECT domain, a flexible hinge links the N-lobe, which contains the E2 binding site, and the C-lobe, which contains the catalytic Cys for Ub transfer. The DOC domain is responsible for substrate binding. Catalytic Cys and phosphorylation sites are indicated [60, 61, 111]