Seroatlas · Human Serome Atlas

ST6GALNAC4

Alpha-N-acetyl-neuraminyl-2,3-beta-galactosyl-1,3-N-acetyl-galactosaminide alpha-2,6-sialyltransferase

Also known as: SIA7D_HUMAN, SIAT3C, SIAT7D, ST6GALNACIV

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession
Q9H4F1
Gene
ST6GALNAC4
Ensembl
ENSG00000136840
Chromosome
9
Canonical length
302 aa
Protein class
Enzymes, Metabolic proteins, Predicted intracellular proteins, Predicted membrane proteins
Subcellular location
Nucleoplasm,Golgi apparatus

OverviewNCBI Gene

The protein encoded by this gene is a type II membrane protein that catalyzes the transfer of sialic acid from CMP-sialic acid to galactose-containing substrates. The encoded protein prefers glycoproteins rather than glycolipids as substrates and shows restricted substrate specificity, utilizing only the trisaccharide sequence Neu5Ac-alpha-2,3-Gal-beta-1,3-GalNAc. In addition, it is involved in the synthesis of ganglioside GD1A from GM1B. The encoded protein is normally found in the Golgi apparatus but can be proteolytically processed to a soluble form. This protein is a member of glycosyltransferase family 29. Transcript variants encoding different isoforms have been found for this gene. Readthrough transcripts exist for this gene and the downstream ST6GALNAC6 gene. [provided by RefSeq, Jan 2022]

Canonical amino-acid sequenceUniProt

302 residues, UniProt reviewed canonical sequence.

>Q9H4F1|ST6GALNAC4
     1  MKAPGRLVLI ILCSVVFSAV YILLCCWAGL PLCLATCLDH HFPTGSRPTV PGPLHFSGYS
    61  SVPDGKPLVR EPCRSCAVVS SSGQMLGSGL GAEIDSAECV FRMNQAPTVG FEADVGQRST
   121  LRVVSHTSVP LLLRNYSHYF QKARDTLYMV WGQGRHMDRV LGGRTYRTLL QLTRMYPGLQ
   181  VYTFTERMMA YCDQIFQDET GKNRRQSGSF LSTGWFTMIL ALELCEEIVV YGMVSDSYCR
   241  EKSHPSVPYH YFEKGRLDEC QMYLAHEQAP RSAHRFITEK AVFSRWAKKR PIVFAHPSWR
   301  TE

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against ST6GALNAC4 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability
Other membrane
Secreted
No
Transmembrane segments
1
Mean surface accessibility (rSASA)
0.31
Highest tissue expression
69 nTPM

Expression across tissuesHPA

Tissue

  • pancreas: 69 nTPM
  • bone marrow: 38 nTPM
  • spleen: 35 nTPM
  • heart muscle: 32 nTPM
  • lung: 26 nTPM
  • blood vessel: 24 nTPM

Single-cell type

  • pdcs: 99 nCPM
  • plasma cells: 87 nCPM
  • megakaryocytes: 74 nCPM
  • alveolar cells type 2: 71 nCPM
  • erythrocyte progenitors: 60 nCPM
  • decidual stromal cells: 49 nCPM

Immune cell

  • plasmacytoid DC: 234 nTPM
  • memory B-cell: 25 nTPM
  • NK-cell: 19 nTPM
  • naive B-cell: 19 nTPM
  • non-classical monocyte: 15 nTPM
  • memory CD8 T-cell: 13 nTPM

Brain region

  • choroid plexus: 20 nTPM
  • cerebral cortex: 18 nTPM
  • cerebellum: 18 nTPM
  • hippocampal formation: 17 nTPM
  • amygdala: 17 nTPM
  • medulla oblongata: 16 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)
1.39
gnomAD pLI
0
gnomAD missense Z
0.76
DepMap mean gene effect
-0.09
DepMap dependency class
none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads ST6GALNAC4 as an antibody target. Whether an autoantibody or antibody against ST6GALNAC4 could matter depends on whether native ST6GALNAC4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

ST6GALNAC4 is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label ST6GALNAC4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/ST6GALNAC4. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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