This is the SPRY domain of HECTD4 (HECT domain-containing protein 4). HECTD4 is a probable E3 ubiquitin-protein ligase, as the HECT (Homologous to the E6-AP Carboxyl Terminus) domain has been identified in proteins that belong to a particular E3 ubiquitin-protein ligase family []. The role of HECTD4 is not known.