Meta-Biol

• Pathways

Cells exposed to castanospermine or 1-deoxynojirimycin (inhibitors of the glucosidase enzymes GCS1 and GANAB), are still able to carry out glycosylation and produce complex glycans. This is due to the existence of an alternative route catalyzed by the enzyme endomannosidase (Moore and Spiro, 1990).
Glycoproteins that pass through this route probably skip or have a reduced interaction with the Calnexin/Calreticulin cycle, and are transported to the cis-golgi through a route that has not been described yet (probably through the general ER to Golgi flow). Here, the Endomannosidase enzyme, which resides on the Golgi membrane (Hardt et al 2005; Hamilton et al 2005) is able to remove the tri-, di-, or mono-glucose substituted mannose on branch A, leading to a deglucosylated N-glycan structure (Lubas and Spiro, 1988).