RPN1
Description
The RPN1 (ribophorin I) is a protein-coding gene located on chromosome 3.
The RPN1 gene encodes a type I integral ribophorin membrane protein found only in the rough endoplasmic reticulum. It is part of an N-oligosaccharyl transferase complex that links high mannose oligosaccharides to asparagine residues in the Asn-X-Ser/Thr consensus motif of nascent polypeptide chains. RPN1 should not be confused with RPN1 in yeast, Drosophila, and C. elegans, which forms part of the regulatory subunit of the 26S proteasome and may mediate binding of ubiquitin-like domains to this proteasome. The human version of this proteasome subunit is PSMD2.
RPN1 is a subunit of the oligosaccharyl transferase (OST) complex, which catalyzes the initial transfer of a defined glycan (Glc(3)Man(9)GlcNAc(2) in eukaryotes) from the lipid carrier dolichol-pyrophosphate to an asparagine residue within an Asn-X-Ser/Thr consensus motif in nascent polypeptide chains. This is the first step in protein N-glycosylation. N-glycosylation occurs cotranslationally, and the OST complex associates with the Sec61 complex at the channel-forming translocon complex that mediates protein translocation across the endoplasmic reticulum (ER). All subunits are required for maximal enzyme activity.
RPN1 is also known as OST1, RBPH1.
