Function

This is an enzyme in the N-glycosilation pathway; it is the second one of the 'trimming' step, right after the N-glycan sugar is attached to a nascent protein in the ER.

Proteins targeted for glycosilation are translated in the ER and modified on a target sequence (usually Asn-X-Ser/Thr) by adding a N-glycan precursor by the OST complex.

This precursor, after being attached to the nascent protein, is modified by a series of glucosidases like GCS1 and GANAB. The removal of glucoses by these enzimes is necessary for the retention of the protein in the ER, and it is a signal to indicate that the modification has occurred.

GCS1 (also known as MOGS) is the first of these glucosidases, the other one is GANAB, followed by other enzymes.

High impact information on GANAB

• In addition, levels of normal hepatocystin and of the glucosidase II alpha subunit are substantially reduced in liver and Epstein-Barr virus-immortalized B lymphoblasts from patients with polycystic liver disease [1].
• RESULTS: Normal hepatocystin localizes to the endoplasmic reticulum, where it assembles with the glucosidase II alpha subunit [1].

References