Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit 1
Function
Subunit of the oligosaccharyl transferase (OST) complex that 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, the first step in protein N-glycosylation (PubMed:31831667). N-glycosylation occurs cotranslationally and the 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 a maximal enzyme activity (By similarity).
Pathway
Protein modification; protein glycosylation.
Post-translational modifications
Ubiquitinated by the ECS(ASB11) complex.
Ufmylated by UFL1 in response to endoplasmic reticulum stress, promoting reticulophagy of endoplasmic reticulum sheets.
Sequence Similarities
Belongs to the OST1 family.
Tissue Specificity
Expressed in all tissues tested.
Cellular localization
- Endoplasmic reticulum membrane
- Single-pass type I membrane protein
- Melanosome
- Identified by mass spectrometry in melanosome fractions from stage I to stage IV.
Alternative names
Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit 1, Dolichyl-diphosphooligosaccharide--protein glycosyltransferase 67 kDa subunit, Ribophorin I, Ribophorin-1, RPN-I, RPN1