Seroatlas · Human Serome Atlas

FSTL1

Follistatin-related protein 1

Also known as: FRP, FSL1, FSTL1_HUMAN, OCC-1, OCC1, tsc36

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

Protein identityUniProt · HPA

UniProt accession
Q12841
Gene
FSTL1
Ensembl
ENSG00000163430
Chromosome
3
Canonical length
308 aa
Protein class
Plasma proteins, Predicted intracellular proteins, Predicted secreted proteins
Subcellular location
Golgi apparatus,Vesicles,Cytosol
Secretome location
Secreted to blood
Quaternary structure
Homodimer

OverviewNCBI Gene

This gene encodes a protein with similarity to follistatin, an activin-binding protein. It contains an FS module, a follistatin-like sequence containing 10 conserved cysteine residues. This gene product is thought to be an autoantigen associated with rheumatoid arthritis. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

308 residues, UniProt reviewed canonical sequence.

>Q12841|FSTL1
     1  MWKRWLALAL ALVAVAWVRA EEELRSKSKI CANVFCGAGR ECAVTEKGEP TCLCIEQCKP
    61  HKRPVCGSNG KTYLNHCELH RDACLTGSKI QVDYDGHCKE KKSVSPSASP VVCYQSNRDE
   121  LRRRIIQWLE AEIIPDGWFS KGSNYSEILD KYFKNFDNGD SRLDSSEFLK FVEQNETAIN
   181  ITTYPDQENN KLLRGLCVDA LIELSDENAD WKLSFQEFLK CLNPSFNPPE KKCALEDETY
   241  ADGAETEVDC NRCVCACGNW VCTAMTCDGK NQKGAQTQTE EEMTRYVQEL QKHQETAEKT
   301  KRVSTKEI

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against FSTL1 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
Secreted
Secreted
Yes
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.38
Highest tissue expression
415 nTPM

Expression across tissuesHPA

Tissue

  • placenta: 415 nTPM
  • adipose tissue: 405 nTPM
  • smooth muscle: 382 nTPM
  • blood vessel: 292 nTPM
  • cervix: 262 nTPM
  • urinary bladder: 243 nTPM

Single-cell type

  • cardiomyocytes: 720 nCPM
  • fibroblasts: 638 nCPM
  • extravillous trophoblasts: 591 nCPM
  • hepatic stellate cells: 407 nCPM
  • leydig cells: 353 nCPM
  • fibro-adipogenic progenitors: 343 nCPM

Immune cell

  • basophil: 12 nTPM
  • total PBMC: 2.6 nTPM
  • plasmacytoid DC: 0.8 nTPM
  • myeloid DC: 0.2 nTPM
  • classical monocyte: 0.1 nTPM
  • neutrophil: 0.1 nTPM

Brain region

  • choroid plexus: 169 nTPM
  • midbrain: 91 nTPM
  • medulla oblongata: 55 nTPM
  • hypothalamus: 43 nTPM
  • thalamus: 43 nTPM
  • spinal cord: 43 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)
0.38
gnomAD pLI
0.89
gnomAD missense Z
0.71
DepMap mean gene effect
0.01
DepMap dependency class
selective

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

InteractionsUniProt · HPA

Protein binding partners of FSTL1 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 FSTL1 as an antibody target. Whether an autoantibody or antibody against FSTL1 could matter depends on whether native FSTL1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

FSTL1 is annotated as secreted, so native FSTL1 circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Source-annotated serology context

The source annotations explicitly mention antibody, autoantibody, autoantigen, or autoimmune context. This is biological context, not study-specific reactivity.

  • This gene product is thought to be an autoantigen associated with rheumatoid arthritis.

Canonical record: https://seroatlas.com/gene/FSTL1. 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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