OST4: Oligosaccharyltransferase Complex Subunit 4
A key component of the N-linked glycosylation machinery, OST4 is a small subunit of the oligosaccharyltransferase (OST) complex essential for protein glycosylation in the endoplasmic reticulum.
Gene Information Card
| Symbol | OST4 |
|---|---|
| Full Name | Oligosaccharyltransferase Complex Subunit 4 |
| Gene Type | Protein coding |
| Chromosomal Location | 2p24.1 |
| NCBI Gene ID | 100128731 ncbi.nlm.nih.gov/gene/100128731 |
| Ensembl ID | ENSG00000204310 |
| UniProt ID | P0C6T2 |
| OMIM ID | 614088 |
| HGNC ID | 33813 |
| Aliases | DC2, MGC10433 |
Description
OST4 encodes a small, 36-amino acid subunit of the oligosaccharyltransferase (OST) complex, which catalyzes the transfer of a preassembled oligosaccharide from a dolichol-linked donor to asparagine residues on nascent polypeptides in the endoplasmic reticulum. This process is essential for proper protein folding, stability, and trafficking. Mutations in OST4 are associated with congenital disorders of glycosylation (CDG) type I.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Congenital disorder of glycosylation type I (CDG-I) | Defects in OST4 impair the transfer of oligosaccharides to proteins, leading to underglycosylation and multisystemic disease. | PMID: 23161690 |
| Colorectal cancer | Altered OST4 expression may affect glycosylation patterns in tumor cells, though direct evidence is limited. | COSMIC |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 15.2 | Medium |
| Kidney | 12.8 | Medium |
| Brain | 8.5 | Low |
| Heart | 6.3 | Low |
| Lung | 5.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 18.4 | High expression |
| HeLa | 14.7 | Medium expression |
| HepG2 | 12.1 | Medium expression |
| K562 | 9.3 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | Rare | Loss of start codon, likely loss of function |
| c.2T>C (p.Met1?) | Missense | Rare | Loss of start codon, likely loss of function |
| c.3G>A (p.Met1?) | Missense | Rare | Loss of start codon, likely loss of function |
Mutation functional classification
Loss of Function (LOF)
Mutations affecting the start codon or introducing premature stop codons are predicted to cause loss of function, leading to reduced OST complex activity and underglycosylation.
Gain of Function (GOF)
No gain-of-function mutations have been reported for OST4.
Dominant Negative (DN)
No dominant-negative mutations have been described for OST4.
View complete mutation data：
Gene Ontology (GO)
| • oligosaccharyltransferase complex (GO:0004576) | • protein N-linked glycosylation (GO:0006487) |
| • endoplasmic reticulum (GO:0005783) | • integral component of membrane (GO:0016021) |
Pathways
• N-glycan biosynthesis (KEGG: hsa00510)
• Protein processing in endoplasmic reticulum (KEGG: hsa04141)
Protein Summary
OST4 is a small, 36-amino acid transmembrane protein that is a subunit of the oligosaccharyltransferase (OST) complex. It is localized to the endoplasmic reticulum membrane and is essential for the catalytic activity of the complex. The protein has a single transmembrane domain and is highly conserved across eukaryotes. Its small size and hydrophobic nature make it critical for complex stability and function.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| OST4 Knockout HEK293 Cell Line | EDJ-KQ11130 | Human | 100128731 | Details Get a Quote |
| OST4 Knockout A-549 Cell Line | EDJ-KQ40358 | Human | 100128731 | Details Get a Quote |
| OST4 Knockout HCT 116 Cell Line | EDJ-KQ40360 | Human | 100128731 | Details Get a Quote |
| OST4 Knockout HeLa Cell Line | EDJ-KQ40361 | Human | 100128731 | Details Get a Quote |
