LMPD Database

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LMP003636

UniProt Annotations

Entry Information
Gene NameSTT3, subunit of the oligosaccharyltransferase complex, homolog A (S. cerevisiae)
Protein EntrySTT3A_MOUSE
UniProt IDP46978
SpeciesMouse
Comments
Comment typeDescription
Catalytic ActivityDolichyl diphosphooligosaccharide + [protein]- L-asparagine = dolichyl diphosphate + a glycoprotein with the oligosaccharide chain attached by N-beta-D-glycosyl linkage to a protein L-asparagine.
FunctionCatalytic subunit of the 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. 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). SST3A seems to be involved in complex substrate specificity. 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 cotranslational glycosylation and mediate glycosylation of sites that have been skipped by STT3A (By similarity). {ECO:0000250}.
PathwayProtein modification; protein glycosylation.
SimilarityBelongs to the STT3 family. {ECO:0000305}.
Subcellular LocationEndoplasmic reticulum membrane; Multi-pass membrane protein.
SubunitComponent of the oligosaccharyltransferase (OST) complex. OST seems to exist in different forms which contain at least RPN1, RPN2, OST48, DAD1, OSTC, KRTCAP2 and either STT3A or STT3B. OST can form stable complexes with the Sec61 complex or with both the Sec61 and TRAP complexes. Also identified as part of a complex which includes CANX, DERL1, DERL2, DDOST/OST48, RPN1, RPN2, SELK, VIMP, STT3A AND VCP. This contains known members of the OST complex and may be a form of this complex (By similarity). {ECO:0000250}.