Regulatory subunit of glucosidase II that cleaves sequentially the 2 innermost alpha-1,3-linked glucose residues from the Glc(2)Man(9)GlcNAc(2) oligosaccharide precursor of immature glycoproteins (By similarity). Required for efficient PKD1/Polycystin-1 biogenesis and trafficking to the plasma membrane of the primary cilia (By similarity). Glycan metabolism; N-glycan metabolism. Heterodimer of a catalytic alpha subunit (GANAB) and a beta subunit (PRKCSH). Binds glycosylated PTPRC. Ubiquitous. Highly expressed in liver, spleen, lung, duodenum, stomach, adrenal gland, pituitary, testis, corpus luteum, uterus and fetal ovary.