Seroatlas · Human Serome Atlas

IGSF21

Immunoglobulin superfamily member 21

Also known as: IGS21_HUMAN, MGC15730, RP11-121A23.1

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

Protein identityUniProt · HPA

UniProt accession
Q96ID5
Gene
IGSF21
Ensembl
ENSG00000117154
Chromosome
1
Canonical length
467 aa
Protein class
Predicted intracellular proteins
Secretome location
Intracellular and membrane

OverviewNCBI Gene

This gene encodes a protein which has two immunoglobulin (Ig) domains and is a member of the immunoglobulin superfamily. Proteins in this superfamily are usually found on or in cell membranes and act as receptors in immune response pathways. [provided by RefSeq, Sep 2011]

Canonical amino-acid sequenceUniProt

467 residues, UniProt reviewed canonical sequence.

>Q96ID5|IGSF21
     1  MRTAPSLRRC VCLLLAAILD LARGYLTVNI EPLPPVVAGD AVTLKCNFKT DGRMREIVWY
    61  RVTDGGTIKQ KIFTFDAMFS TNYSHMENYR KREDLVYQST VRLPEVRISD NGPYECHVGI
   121  YDRATREKVV LASGNIFLNV MAPPTSIEVV AADTPAPFSR YQAQNFTLVC IVSGGKPAPM
   181  VYFKRDGEPI DAVPLSEPPA ASSGPLQDSR PFRSLLHRDL DDTKMQKSLS LLDAENRGGR
   241  PYTERPSRGL TPDPNILLQP TTENIPETVV SREFPRWVHS AEPTYFLRHS RTPSSDGTVE
   301  VRALLTWTLN PQIDNEALFS CEVKHPALSM PMQAEVTLVA PKGPKIVMTP SRARVGDTVR
   361  ILVHGFQNEV FPEPMFTWTR VGSRLLDGSA EFDGKELVLE RVPAELNGSM YRCTAQNPLG
   421  STDTHTRLIV FENPNIPRGT EDSNGSIGPT GARLTLVLAL TVILELT

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against IGSF21 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
Cell surface
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.43
Highest tissue expression
97 nTPM

Expression across tissuesHPA

Tissue

  • cerebellum: 97 nTPM
  • cerebral cortex: 59 nTPM
  • hippocampal formation: 43 nTPM
  • amygdala: 30 nTPM
  • midbrain: 20 nTPM
  • hypothalamus: 20 nTPM

Single-cell type

  • retinal bipolar cells: 333 nCPM
  • microglia: 313 nCPM
  • oligodendrocyte progenitor cells: 257 nCPM
  • tuft cells: 196 nCPM
  • brain excitatory neurons: 122 nCPM
  • macrophages: 120 nCPM

Immune cell

  • basophil: 0 nTPM
  • classical monocyte: 0 nTPM
  • eosinophil: 0 nTPM
  • gdT-cell: 0 nTPM
  • intermediate monocyte: 0 nTPM
  • MAIT T-cell: 0 nTPM

Brain region

  • cerebellum: 78 nTPM
  • cerebral cortex: 78 nTPM
  • white matter: 60 nTPM
  • basal ganglia: 55 nTPM
  • hippocampal formation: 53 nTPM
  • pons: 48 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)
0.53
gnomAD pLI
0.21
gnomAD missense Z
0.32
DepMap mean gene effect
-0.02
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

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads IGSF21 as an antibody target. Whether an autoantibody or antibody against IGSF21 could matter depends on whether native IGSF21 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

IGSF21 is annotated at the cell surface, where native IGSF21 is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label IGSF21 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/IGSF21. 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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