Oligosaccharyltransferase complex

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.

Apparently, the expression of OST subunits depends on the cell context and is often altered in malignant cells, contributing to tumor cell survival and proliferation. A recently developed OST inhibitor has revealed this enzyme as a potential target for the treatment of incurable drug-resistant tumors.

1. Harada Y et al (2019) Oligosaccharyltransferase: A Gatekeeper of Health and Tumor Progression. Int J Mol Sci 20: 6074.