Seroatlas · Human Serome Atlas

FSTL4

Follistatin-related protein 4

Also known as: FSTL4_HUMAN, KIAA1061

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

Protein identityUniProt · HPA

UniProt accession
Q6MZW2
Gene
FSTL4
Ensembl
ENSG00000053108
Chromosome
5
Canonical length
842 aa
Protein class
Predicted intracellular proteins, Predicted secreted proteins
Subcellular location
Vesicles
Secretome location
Secreted to blood

OverviewNCBI Gene

Predicted to enable brain-derived neurotrophic factor binding activity and calcium ion binding activity. Predicted to be involved in cell differentiation and regulation of BMP signaling pathway. Predicted to act upstream of or within negative regulation of brain-derived neurotrophic factor receptor signaling pathway; negative regulation of collateral sprouting; and negative regulation of dendritic spine development. Predicted to be located in secretory granule. Predicted to be active in extracellular region. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

842 residues, UniProt reviewed canonical sequence.

>Q6MZW2|FSTL4
     1  MKPGGFWLHL TLLGASLPAA LGWMDPGTSR GPDVGVGESQ AEEPRSFEVT RREGLSSHNE
    61  LLASCGKKFC SRGSRCVLSR KTGEPECQCL EACRPSYVPV CGSDGRFYEN HCKLHRAACL
   121  LGKRITVIHS KDCFLKGDTC TMAGYARLKN VLLALQTRLQ PLQEGDSRQD PASQKRLLVE
   181  SLFRDLDADG NGHLSSSELA QHVLKKQDLD EDLLGCSPGD LLRFDDYNSD SSLTLREFYM
   241  AFQVVQLSLA PEDRVSVTTV TVGLSTVLTC AVHGDLRPPI IWKRNGLTLN FLDLEDINDF
   301  GEDDSLYITK VTTIHMGNYT CHASGHEQLF QTHVLQVNVP PVIRVYPESQ AQEPGVAASL
   361  RCHAEGIPMP RITWLKNGVD VSTQMSKQLS LLANGSELHI SSVRYEDTGA YTCIAKNEVG
   421  VDEDISSLFI EDSARKTLAN ILWREEGLSV GNMFYVFSDD GIIVIHPVDC EIQRHLKPTE
   481  KIFMSYEEIC PQREKNATQP CQWVSAVNVR NRYIYVAQPA LSRVLVVDIQ AQKVLQSIGV
   541  DPLPAKLSYD KSHDQVWVLS WGDVHKSRPS LQVITEASTG QSQHLIRTPF AGVDDFFIPP
   601  TNLIINHIRF GFIFNKSDPA VHKVDLETMM PLKTIGLHHH GCVPQAMAHT HLGGYFFIQC
   661  RQDSPASAAR QLLVDSVTDS VLGPNGDVTG TPHTSPDGRF IVSAAADSPW LHVQEITVRG
   721  EIQTLYDLQI NSGISDLAFQ RSFTESNQYN IYAALHTEPD LLFLELSTGK VGMLKNLKEP
   781  PAGPAQPWGG THRIMRDSGL FGQYLLTPAR ESLFLINGRQ NTLRCEVSGI KGGTTVVWVG
   841  EV

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against FSTL4 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)
0.29
Highest tissue expression
5.8 nTPM

Expression across tissuesHPA

Tissue

  • cerebral cortex: 5.8 nTPM
  • urinary bladder: 5.6 nTPM
  • basal ganglia: 4.6 nTPM
  • cerebellum: 4.1 nTPM
  • placenta: 3.6 nTPM
  • retina: 3.6 nTPM

Single-cell type

  • cone photoreceptor cells: 573 nCPM
  • renal connecting tubule cells: 332 nCPM
  • retinal amacrine cells: 310 nCPM
  • retinal bipolar cells: 291 nCPM
  • brain inhibitory neurons: 270 nCPM
  • thyrotrophs: 267 nCPM

Immune cell

  • basophil: 1.3 nTPM
  • memory B-cell: 0.8 nTPM
  • MAIT T-cell: 0.6 nTPM
  • naive B-cell: 0.6 nTPM
  • memory CD4 T-cell: 0.5 nTPM
  • naive CD4 T-cell: 0.5 nTPM

Brain region

  • thalamus: 89 nTPM
  • cerebral cortex: 72 nTPM
  • cerebellum: 67 nTPM
  • white matter: 64 nTPM
  • amygdala: 57 nTPM
  • basal ganglia: 57 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)
0.44
gnomAD pLI
0.02
gnomAD missense Z
1.01
DepMap mean gene effect
0.07
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% 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 FSTL4 as an antibody target. Whether an autoantibody or antibody against FSTL4 could matter depends on whether native FSTL4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

FSTL4 is annotated as secreted, so native FSTL4 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.

Annotation status

The present source text does not explicitly label FSTL4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/FSTL4. 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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