This domain consists of the SPRY subdomain similar to those found at the N-terminus of the HECT (homologous to the E6AP carboxyl terminus) protein, a C-terminal catalytic domain of a subclass of ubiquitin-protein ligase (E3). HECT E3 binds specific ubiquitin-conjugating enzymes (E2), accepts ubiquitin from E2, transfers ubiquitin to substrate lysine side chains, and transfers additional ubiquitin molecules to the end of growing ubiquitin chains. It has a prominent role in protein trafficking and immune response, and is involved in crucial signaling pathways implicated in tumorigenesis.
Jiyao W et al.(2023). "The conserved domain database in 2023.",