InnateDB: Systems Biology of the Innate Immune Response

Homo sapiens Protein: STT3B

Summary

InnateDB Protein

IDBP-23486.5

Last Modified

2014-10-13 [Report errors or provide feedback]

Gene Symbol

STT3B

Protein Name

STT3, subunit of the oligosaccharyltransferase complex, homolog B (S. cerevisiae)

Synonyms

Species

Homo sapiens

Ensembl Protein

ENSP00000295770

InnateDB Gene

IDBG-23484 (STT3B)

Protein Structure

UniProt Annotation

Function

Catalytic 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). STT3B is present in a small subset of OST complexes and mediates both cotranslational and post-translational N-glycosylation of target proteins: STT3B-containing complexes are required for efficient cotranslational glycosylation and while they are less competent than STT3A-containing complexes for cotranslational glycosylation, they have the ability to mediate glycosylation of some nascent sites that are not accessible for STT3A. STT3B-containing complexes also act post-translationally and mediate modification of skipped glycosylation sites in unfolded proteins. Plays a role in ER-associated degradation (ERAD) pathway that mediates ubiquitin-dependent degradation of misfolded endoplasmic reticulum proteins by mediating N-glycosylation of unfolded proteins, which are then recognized by the ERAD pathway and targeted for degradation. Mediates glycosylation of the disease variant AMYL- TTR 'Asp-38' of TTR at 'Asn-118', leading to its degradation. {ECO:0000269PubMed:19167329, ECO:0000269PubMed:22607976}.

Subcellular Localization

Endoplasmic reticulum membrane; Multi-pass membrane protein.

Disease Associations

Congenital disorder of glycosylation 1X (CDG1X) [MIM:615597]: A multisystem disorder caused by a defect in glycoprotein biosynthesis and characterized by under-glycosylated serum glycoproteins. Congenital disorders of glycosylation result in a wide variety of clinical features, such as defects in the nervous system development, psychomotor retardation, dysmorphic features, hypotonia, coagulation disorders, and immunodeficiency. The broad spectrum of features reflects the critical role of N- glycoproteins during embryonic development, differentiation, and maintenance of cell functions. {ECO:0000269PubMed:23842455}. Note=The disease is caused by mutations affecting the gene represented in this entry.

Tissue Specificity

Expressed in heart, brain, placenta, lung, liver, muscle, kidney and pancreas. Expressed in skin fibroblasts (at protein level). {ECO:0000269PubMed:12887896}.

Comments

Interactions

Number of Interactions

This gene and/or its encoded proteins are associated with 26 experimentally validated interaction(s) in this database.
They are also associated with 1 interaction(s) predicted by orthology.

Experimentally validated
Total	26 [view]
Protein-Protein	26 [view]
Protein-DNA	0
Protein-RNA	0
DNA-DNA	0
RNA-RNA	0
DNA-RNA	0

Predicted by orthology
Total	1 [view]

Gene Ontology

Molecular Function

Accession	GO Term
GO:0004576	oligosaccharyl transferase activity
GO:0004579	dolichyl-diphosphooligosaccharide-protein glycotransferase activity

Biological Process

GO:0006486	protein glycosylation
GO:0006516	glycoprotein catabolic process
GO:0006986	response to unfolded protein
GO:0018279	protein N-linked glycosylation via asparagine
GO:0030433	ER-associated ubiquitin-dependent protein catabolic process
GO:0043686	co-translational protein modification
GO:0043687	post-translational protein modification