Skip to content
GenoLensGenoLens

STT3A

Chr 11q24.2

STT3 oligosaccharyltransferase complex catalytic subunit A

Aliases:
TMC, MGC9042, STT3-A
MANE:
ENST00000392708.9
OMIM: 601134 ↗NCBI: 3703 ↗Ensembl ↗

Annotations refreshed 1 month ago.

Predicted protein structure

Clinical relevance (Genomics England PanelApp)

Diagnostic Grade (Green)

  • Congenital disorders of glycosylation

    BOTH monoallelic and biallelic, autosomal or pseudoautosomal

  • DDG2P

    MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown

  • Fetal anomalies

    BOTH monoallelic and biallelic, autosomal or pseudoautosomal

  • Intellectual disability

    BOTH monoallelic and biallelic, autosomal or pseudoautosomal

  • Likely inborn error of metabolism

    BOTH monoallelic and biallelic, autosomal or pseudoautosomal

  • Skeletal dysplasia

    MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted

  • Childhood onset dystonia, chorea or related movement disorder

Disease associations (Open Targets)

  • congenital disorder of glycosylation, type Iw, autosomal dominant

    0.75

  • STT3A-congenital disorder of glycosylation

    0.74

  • dengue disease

    0.50

  • COVID-19

    0.37

  • Second degree atrioventricular block

    0.25

  • actinic keratosis

    0.23

  • hereditary disease

    0.19

  • oral cavity neoplasm

    0.18

  • microcephaly

    0.11

  • neoplasm

    0.09

Score is the Open Targets composite evidence score (0-1). Higher = stronger gene-disease association.

Protein function (UniProt)

Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit STT3A

Catalytic subunit of the oligosaccharyl transferase (OST) complex that catalyzes the initial transfer of a defined glycan (Glc(3)Man(9)GlcNAc(2) in eukaryotes) from the lipid carrier dolichol-pyrophosphate to an asparagine residue within an Asn-X-Ser/Thr consensus motif in nascent polypeptide chains, the first step in protein N-glycosylation (PubMed:19167329, PubMed:31296534, PubMed:31831667, PubMed:34653363, PubMed:38670073, PubMed:39509507). 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) (PubMed:19167329, PubMed:31296534, PubMed:31831667, PubMed:34653363, PubMed:38670073, PubMed:39509507). All subunits are required for a maximal enzyme activity (PubMed:19167329, PubMed:31831667, PubMed:34653363). This subunit contains the active site and the acceptor peptide and donor lipid-linked oligosaccharide (LLO) binding pockets (PubMed:19167329). 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 post-translational glycosylation and mediate glycosylation of sites that have been skipped by STT3A (PubMed:19167329, PubMed:38670073, PubMed:39509507). STT3A-containing OST-A complex is also required to prevent hyperglycosylation of some target proteins by preventing glycosylation of facultative sites before folding of target proteins is completed (PubMed:39509507)

Diseases associated with STT3A

Curated MONDO disease pages that list STT3A among their top associated genes.

Data sources: HGNC (CC BY 4.0), AlphaFold (CC BY 4.0, Jumper et al. Nature 2021), Genomics England PanelApp (CC BY 4.0), ClinGen, Open Targets (CC0), UniProt.

Not for sole clinical decision-making. Always verify against primary sources.