HECT Domain And Ankyrin Repeat Containing, E3 Ubiquitin Protein Ligase 1 (HACE1)

HACE1 has ubiquitin ligase activity, utilizing UBCH7 (UBE2L3) as a candidate partner E2 enzyme. HACE1 associated with ubiquitinated proteins and components of the 26S proteasomal complex, indicating that at least some proteins targeted for ubiquitination by HACE1 are degraded by the proteasome.The predicted 909-amino acid protein has a calculated molecular mass of about 103 kD and contains 6 N-terminal ankyrin repeats and a C-terminal HECT domain.By subcellular fractionation and immunofluorescence studies in NIH3T3 fibroblasts, the authors found that HACE1 localized primarily to endoplasmic reticulum and the cytoplasm with small amounts of endogenous protein present in other fractions.