ER Degradation Enhancer, Mannosidase Alpha Like Protein 1 (EDEM1)

EDEM1 has an mRNA of 6 kb, including a long 3-prime untranslated region of 4 kb. Mouse and human EDEM proteins share 92% identity. The human endoplasmic reticulum alpha-1,2-mannosidase I (MAN1B1) has the highest similarity to mouse Edem among members of the alpha-1,2-mannosidase family. Expression of Edem mRNA was induced by various types of ER stress. Although the luminal region of Edem is similar to that of class I alpha-1,2-mannosidases involved in N-glycan processing, Edem does not have enzymatic activity, consistent with the lack of the 2 cys residues conserved in all class I alpha-1,2-mannosidases. Overexpression of Edem in human embryonic kidney 293 cells accelerated degradation of misfolded alpha-1-antitrypsin , and Edem bound to this misfolded glycoprotein.