• This functions as a heterodimeric enzyme complex GANAB (active part)/PRKCHS (inactive part) to provide a-glucosidase II activity.
• This removes the second and third α(1-3)Glc from Glc₂Man₉GlcNAc₂-Asn during N-glycosylation processing to produce Man₉GlcNAc₂-Asn.
• In addition to N-glycan processing, α-Glucosidase II is also involved in protein folding quality control in the ER.
• Glycoproteins containing a single α(1-3)Glc residue is recognized by the ER lectin chaperones, calreticulin (CRT) and calnexin (CNX), that are complexed with protein disulfide isomerase isoforms and aid in folding and maturation of glycoproteins.
• Upon transient release from the lectin chaperones, α-Glucosidase II clips the remaining Glc and the protein moves to the next steps of processing provided it is well folded.
• If the glycoprotein is incompletely folded, the misfolded protein is recognized in the context of its N-glycan by the folding sensor UGGT. UGGT puts back one α(1-3)Glc that is removed by GANAB, and refolding is again attempted by CNX/CRT.
• This enzyme activity is inhibited by 1-deoxynojirimycin, N-5-carboxypentyl-dNM, and castanospermine.
• Mutations in PRKCSH were detected in patients with autosomal dominant polycystic liver disease (ADPLD).