Summary: Neutral alpha-glucosidase AB (GANAB)

GANAB encodes the catalytic subunit of glucosidase II, an endoplasmic reticulum enzyme that sequentially removes the two innermost alpha-1,3-linked glucose residues from oligosaccharide precursors during N-linked glycoprotein maturation (UniProt: Q14697). The enzyme is also required for proper maturation and cell surface localization of polycystin-1 and polycystin-2, key proteins involved in ciliary function.

GANAB is primarily expressed in tissues requiring extensive glycoprotein synthesis and processing. Mutations cause autosomal dominant polycystic kidney disease 3 (PKD3), characterized by progressive cyst formation in kidneys and liver (UniProt: Q14697, MIM 600666).

In Alzheimer's Disease, GANAB shows ambiguous regulation across subcellular fractions of post-mortem human brain tissue. A multiplex TMT proteomics study comparing AD samples to age-matched controls across four subcellular fractions (P2, P3, S2, S3) detected a modest mean log2 fold-change of 0.26 (Chaparral AD proteomics), suggesting minimal or variable changes depending on cellular compartment. The biological significance of this finding remains unclear.