GANAB

This gene encodes the alpha subunit of glucosidase II and a member of the glycosyl hydrolase 31 family of proteins. The heterodimeric enzyme glucosidase II plays a role in protein folding and quality control by cleaving glucose residues from immature glycoproteins in the endoplasmic reticulum. Expression of the encoded protein is elevated in lung tumor tissue and in response to UV irradiation. Mutations in this gene cause autosomal-dominant polycystic kidney and liver disease.

Full Name

glucosidase II alpha subunit

Function

Catalytic subunit of glucosidase II that cleaves sequentially the 2 innermost alpha-1,3-linked glucose residues from the Glc2Man9GlcNAc2 oligosaccharide precursor of immature glycoproteins (PubMed:10929008).

Required for PKD1/Polycystin-1 and PKD2/Polycystin-2 maturation and localization to the cell surface and cilia (PubMed:27259053).

Biological Process

Carbohydrate metabolic process Source: InterPro
N-glycan processing Source: UniProtKB

Cellular Location

Endoplasmic reticulum; Golgi apparatus; Melanosome. Identified by mass spectrometry in melanosome fractions from stage I to stage IV.

Involvement in disease

Polycystic kidney disease 3 with or without polycystic liver disease (PKD3):
A form of polycystic kidney disease, a disorder characterized by progressive formation and enlargement of cysts in both kidneys, typically leading to end-stage renal disease in adult life. Cysts also occur in other organs, particularly the liver. PKD3 inheritance is autosomal dominant. GANAB variations may act as a disease modifier in autosomal dominant polycystic liver disease in patients who have causative mutations in other genes, such as PKHD1 or ALG8.