| Function | Catalytic 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. 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. This subunit contains the active site and the acceptor peptide and donor lipid-linked oligosaccharide (LLO) binding pockets. STT3A is present in the majority of OST complexes and mediates cotranslational N-glycosylation of most sites on target proteins, while STT3B-containing complexes are required for efficient post-translational glycosylation and mediate glycosylation of sites that have been skipped by STT3A. |
| Protein Name | Dolichyl-Diphosphooligosaccharide--Protein Glycosyltransferase Subunit Stt3aOligosaccharyl Transferase Subunit Stt3aStt3-AB5Integral Membrane Protein 1Transmembrane Protein Tmc |
| Database Links | Reactome: R-HSA-446203Reactome: R-HSA-9694548 |
| Cellular Localisation | Endoplasmic ReticulumEndoplasmic Reticulum MembraneMulti-Pass Membrane Protein |
| Alternative Protein Names | Dolichyl-Diphosphooligosaccharide--Protein Glycosyltransferase Subunit Stt3a proteinOligosaccharyl Transferase Subunit Stt3a proteinStt3-A proteinB5 proteinIntegral Membrane Protein 1 proteinTransmembrane Protein Tmc proteinSTT3A proteinITM1 proteinTMC protein |
Information sourced from Uniprot.org
