OSTC Gene: Structure, Function, and Clinical Significance
A comprehensive overview of the OSTC gene, encoding the oligosaccharyltransferase complex non-catalytic subunit, including its genomic context, expression, and disease associations.
Gene Information Card
| Symbol | OSTC |
|---|---|
| Full Name | Oligosaccharyltransferase Complex Non-Catalytic Subunit |
| Gene Type | Protein coding |
| Chromosomal Location | 4q25 |
| NCBI Gene ID | 58534 ncbi.nlm.nih.gov/gene/58534 |
| Ensembl ID | ENSG00000151503 |
| UniProt ID | Q9NRP0 |
| OMIM ID | 617233 |
| HGNC ID | 26125 |
| Aliases | DC2, MGC26577 |
Description
The OSTC gene encodes the non-catalytic subunit of the oligosaccharyltransferase (OST) complex, which is essential for N-linked glycosylation of proteins in the endoplasmic reticulum. OSTC is a component of the OST complex that transfers a high-mannose oligosaccharide from dolichol to asparagine residues on nascent polypeptides. While OSTC does not possess catalytic activity, it is required for the stability and proper assembly of the OST complex. Mutations in OSTC have been associated with congenital disorders of glycosylation, characterized by multisystem abnormalities.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Congenital disorder of glycosylation (CDG) type I | Pathogenic variants in OSTC impair N-glycosylation, leading to hypoglycosylation of multiple proteins and resulting in multisystem disease. | OMIM: 617233; ClinVar: pathogenic variants reported |
| Intellectual disability (in some patients) | OSTC mutations may affect neuronal glycosylation, contributing to neurodevelopmental deficits. | Case reports in literature (e.g., PMID: 27573165) |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 9.8 | Low |
| Liver | 7.2 | Low |
| Kidney | 6.5 | Low |
| Testis | 12.3 | Medium |
| Thyroid | 11.0 | Medium |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 15.2 | Ubiquitous expression |
| HEK293 | 14.8 | Ubiquitous expression |
| K562 | 10.5 | Moderate expression |
| A549 | 12.1 | Moderate expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.506G>A (p.Arg169His) | Missense | Rare (found in a single CDG patient) | Impairs OST complex assembly and N-glycosylation |
| c.1A>G (p.Met1?) | Start codon loss | Rare | Loss of protein expression, leading to OST complex dysfunction |
Mutation functional classification
Loss of Function (LOF)
Most OSTC mutations are loss-of-function, leading to reduced OST complex stability and impaired N-glycosylation.
Gain of Function (GOF)
No gain-of-function mutations have been reported for OSTC.
Dominant Negative (DN)
Some missense mutations may exert a dominant-negative effect by disrupting the OST complex assembly, but evidence is limited.
View complete mutation data：
Gene Ontology (GO)
| • protein N-linked glycosylation (GO:0006487) | • oligosaccharyltransferase complex (GO:0008250) |
| • integral component of membrane (GO:0016021) | • endoplasmic reticulum membrane (GO:0005789) |
Pathways
• N-glycan biosynthesis (KEGG: hsa00510)
• Protein processing in endoplasmic reticulum (KEGG: hsa04141)
Protein Summary
OSTC is a 128-amino acid protein with a single transmembrane domain, localized to the endoplasmic reticulum membrane. It is a non-catalytic subunit of the OST complex, which is composed of multiple subunits (e.g., STT3A, STT3B, RPN1, etc.). OSTC is essential for the stability of the OST complex and its proper localization. It interacts with other subunits to facilitate the transfer of oligosaccharides to nascent proteins. Defects in OSTC lead to abnormal glycosylation, affecting various proteins and causing clinical phenotypes.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| OSTC Knockout HEK293 Cell Line | EDJ-KQ14640 | Human | 58505 | Details Get a Quote |
| OSTC Knockout HCT 116 Cell Line | EDJ-KQ44922 | Human | 58505 | Details Get a Quote |
| OSTC Knockout HeLa Cell Line | EDJ-KQ44923 | Human | 58505 | Details Get a Quote |
| OSTC Knockout A-549 Cell Line | EDJ-KQ65450 | Human | 58505 | Details Get a Quote |
