Processing alpha glucosidase I; ER type II integral membrane N-glycoprotein involved in assembly of cell wall beta 1,6 glucan and asparagine-linked protein glycosylation; has a role in ER protein quality control and sensing of ER stress; ortholog of the human mannosyl-oligosaccharide glucosidase MOGS, defects of which are associated with congenital disorders of glycosylation