Oligosaccharyltransferase (OST) is a multicolumn membrane protein complex that catalyzes the attachment of glycans to selected Asn residues in nascent polypeptides in the lumen of the endoplasmic reticulum.
This process, termed N-glycosylation, is a fundamental post-translational protein modification involved in protein quality control, transport, signal transduction, and cell-cell communication.
N-glycosylation is essential for homeostasis at the systemic and cellular levels. Mutationten in genes encoding OST subunits often leads to the development of complex genetic disorders.