Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit 4 (Ost4)

Acts as component of this N-oligosaccharyl transferase (OST) complex which catalyzes the transfer of a high mannose oligosaccharide from a lipid-linked oligosaccharide donor to an asparagine residue within an Asn-X-Ser/Thr consensus motif in nascent polypeptide chains. Required for efficient N- glycosylation.

Specifically involved in preserving stability of STT3A-containing OST complexes. .