This domain occurs within alpha-1,2-mannosidases, which remove alpha-1,2-linked mannose residues from Man(9)(GlcNAc)(2) by hydrolysis. They are critical for the maturation of N-linked oligosaccharides and ER-associated degradation [1].
Liu Y, Choudhury P, Cabral CM, Sifers RN.
Oligosaccharide modification in the early secretory pathway directs the selection of a misfolded glycoprotein for degradation by the proteasome.
J. Biol. Chem. 274 5861-7 1999
[PubMed: 10026209] http://dx.doi.org/10.1074/jbc.274.9.5861