This entry represents a group of alpha-1,2-specific exomannosidases that are involved in endoplasmic reticulum-associated degradation (ERAD), including EDEM1/2/3 from humans, Mnl1 from yeasts and MNS4/5 from Arabidopsis. Mnl1 forms a complex with Pdi1 to process unfolded protein-bound Man8GlcNAc2 oligosaccharides to Man7GlcNAc2, promoting degradation in unfolded protein response []. In humans, mannose trimming from Man8GlcNAc2 to Man7GlcNAc2 is performed mainly by EDEM3 and to a lesser extent by EDEM1, while EDEM2 catalyses the first mannose trimming step from Man9GlcNAc2 []. EDEM1 has been shown to recognise and deliver misfolded proteins to the SEL1L-containing ERAD complex []. MNS4/5 function in the formation of unique N-glycan structures that are specifically recognized by components of the endoplasmic reticulum-associated degradation (ERAD) machinery, which leads to the degradation of misfolded glycoproteins [].
