STT3 subunit of the oligosaccharyltransferase complex homolog A
Transmembrane protein TMC
FunctionComponent of the N-oligosaccharyl transferase enzyme 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.
Tissue specificityExpressed at high levels in placenta, liver, muscle and pancreas, and at very low levels in brain, lung and kidney. Expressed in skin fibroblasts (at protein level).