Regulatory subunit of glucosidase II that cleaves sequentially the 2 innermost alpha-1,3-linked glucose residues from the Glc2Man9GlcNAc2 oligosaccharide precursor of immature glycoproteins. Required for efficient PKD1/Polycystin-1 biogenesis and trafficking to the plasma membrane of the primary cilia. This protein is involved in the pathway N-glycan metabolism, which is part of Glycan metabolism. View all proteins of this organism that are known to be involved in the pathway N-glycan metabolism and in Glycan metabolism. Mutations in this gene have been associated with the autosomal dominant polycystic liver disease. Alternative splicing results in multiple transcript variants.