Seroatlas · Human Serome Atlas

STX18

Syntaxin-18

Also known as: STX18_HUMAN, Ufe1

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

Protein identityUniProt · HPA

UniProt accession
Q9P2W9
Gene
STX18
Ensembl
ENSG00000168818
Chromosome
4
Canonical length
335 aa
Protein class
Predicted intracellular proteins, Predicted membrane proteins
Subcellular location
Endoplasmic reticulum,Plasma membrane

OverviewNCBI Gene

This gene encodes a member of the syntaxin family of soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) which is part of a membrane tethering complex that includes other SNAREs and several peripheral membrane proteins, and is involved in vesicular transport between the endoplasmic reticulum (ER) and the Golgi complex. The encoded protein is important for the organization of the smooth, rough, and exit site ER subdomains. A pseudogene of this gene has been identified. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Oct 2016]

Canonical amino-acid sequenceUniProt

335 residues, UniProt reviewed canonical sequence.

>Q9P2W9|STX18
     1  MAVDITLLFR ASVKTVKTRN KALGVAVGGG VDGSRDELFR RSPRPKGDFS SRAREVISHI
    61  GKLRDFLLEH RKDYINAYSH TMSEYGRMTD TERDQIDQDA QIFMRTCSEA IQQLRTEAHK
   121  EIHSQQVKEH RTAVLDFIED YLKRVCKLYS EQRAIRVKRV VDKKRLSKLE PEPNTKTRES
   181  TSSEKVSQSP SKDSEENPAT EERPEKILAE TQPELGTWGD GKGEDELSPE EIQMFEQENQ
   241  RLIGEMNSLF DEVRQIEGRV VEISRLQEIF TEKVLQQEAE IDSIHQLVVG ATENIKEGNE
   301  DIREAIKNNA GFRVWILFFL VMCSFSLLFL DWYDS

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against STX18 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)
0.47
Highest tissue expression
113 nTPM

Expression across tissuesHPA

Tissue

  • cervix: 113 nTPM
  • endometrium: 51 nTPM
  • fallopian tube: 46 nTPM
  • testis: 29 nTPM
  • kidney: 27 nTPM
  • choroid plexus: 23 nTPM

Single-cell type

  • endometrial luminal cells: 463 nCPM
  • endometrial glandular cells: 453 nCPM
  • endometrial ciliated cells: 393 nCPM
  • choroid plexus epithelial cells: 276 nCPM
  • renal collecting duct intercalated cells: 216 nCPM
  • distal convoluted tubule cells: 213 nCPM

Immune cell

  • plasmacytoid DC: 38 nTPM
  • myeloid DC: 24 nTPM
  • non-classical monocyte: 21 nTPM
  • MAIT T-cell: 18 nTPM
  • NK-cell: 17 nTPM
  • memory B-cell: 17 nTPM

Brain region

  • choroid plexus: 29 nTPM
  • pons: 20 nTPM
  • hypothalamus: 20 nTPM
  • medulla oblongata: 18 nTPM
  • basal ganglia: 18 nTPM
  • midbrain: 18 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)
0.96
gnomAD pLI
0
gnomAD missense Z
0.7
DepMap mean gene effect
-1.16
DepMap dependency class
common

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 5% 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

InteractionsUniProt · HPA

Protein binding partners of STX18 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads STX18 as an antibody target. Whether an autoantibody or antibody against STX18 could matter depends on whether native STX18 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

STX18 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 STX18 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/STX18. 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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