HECT domain E3 ubiquitin protein ligase 4 (HECTD4)

HECT domain E3 ubiquitin protein ligase 4 (HECTD4) is an enzyme belonging to the HECT (Homologous to E6AP C-terminal) E3 ubiquitin ligase family[1][3]. Like other HECT-type E3 ligases, HECTD4 confers specificity in the ubiquitin-proteasome system by transferring ubiquitin from E2 conjugating enzymes to lysine residues on substrate proteins, targeting them for proteasomal degradation[1][3]. HECTD4 contains a highly conserved cysteine residue in its C-terminal HECT domain, crucial for its catalytic activity[2]. Recently, HECTD4 has been identified as a tumor and metastasis suppressor in breast cancer models by mediating the ubiquitination and degradation of cyclooxygenase-2 (COX-2) and its regulatory kinase MKK7; loss of HECTD4 enhances COX-2 expression, promoting anchorage-independent growth and metastatic potential[2]. Although specific drugs targeting HECTD4 are not described, modulation of its pathway (notably COX-2 inhibition) reverses its functional effects in cancer cells, suggesting therapeutic potential for intervention at this axis[2]. The broader HECT E3 ligase family is linked to regulation of cell proliferation, migration, apoptosis, and multiple disease processes, most prominently in oncology[1][2][3].

Other names

Probable E3 ubiquitin-protein ligase HECTD4C12orf51KIAA0614FLJ34154HECT domain-containing protein 4HECT-type E3 ubiquitin transferase HECTD4C12ord51HEELNEDSSCCPOTAGEAF-1 specific protein phosphatasetransmembrane protein C12orf51

Drugs targeting this pathway would likely act by modulating ubiquitin ligase activity, altering substrate degradation, or stabilizing/destabilizing protein targets such as COX-2[2]