Seroatlas · Human Serome Atlas

FAM209B

Protein FAM209B

Also known as: C20orf107, dJ1153D9.4, F209B_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q5JX69
Gene
FAM209B
Ensembl
ENSG00000213714
Chromosome
20
Canonical length
171 aa
Protein class
Predicted membrane proteins

OverviewNCBI Gene

Predicted to be involved in acrosome assembly. Located in acrosomal vesicle. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

171 residues, UniProt reviewed canonical sequence.

>Q5JX69|FAM209B
     1  MWTLKSSLVL LLCLTCSYAF MFSSLRQKTS EPQGKVPCGE HFRIRQNLPE HTQGWLGSKW
    61  LWLLFAVVPF VILQCQRDSE KNKEQSPPGL RGFPFRTPLK KNQNASLYKD CVFNTLNELE
   121  VELLKFVSEV QNLKGAMATG SGSNLKLRRS EMPADPYHVT ICKIWGEESS S

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against FAM209B 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
Intracellular
Secreted
No
Transmembrane segments
1
Mean surface accessibility (rSASA)
0.57
Highest tissue expression
108 nTPM

Expression across tissuesHPA

Tissue

  • testis: 108 nTPM
  • bone marrow: 11 nTPM
  • spleen: 2.5 nTPM
  • lymph node: 1.2 nTPM
  • skin: 1.1 nTPM
  • lung: 0.9 nTPM

Single-cell type

  • early spermatids: 2,104 nCPM
  • late primary spermatocytes: 553 nCPM
  • late spermatids: 241 nCPM
  • neutrophils: 11 nCPM
  • sertoli cells: 6.5 nCPM
  • paneth cells: 3.9 nCPM

Immune cell

  • eosinophil: 1 nTPM
  • gdT-cell: 0.6 nTPM
  • neutrophil: 0.5 nTPM
  • classical monocyte: 0.3 nTPM
  • memory CD8 T-cell: 0.3 nTPM
  • myeloid DC: 0.2 nTPM

Brain region

  • cerebral cortex: 1 nTPM
  • choroid plexus: 0.6 nTPM
  • hypothalamus: 0.5 nTPM
  • medulla oblongata: 0.5 nTPM
  • midbrain: 0.5 nTPM
  • pons: 0.5 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)
1.9
gnomAD pLI
0
gnomAD missense Z
0.45
DepMap mean gene effect
-0.08
DepMap dependency class
none

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

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads FAM209B as an antibody target. Whether an autoantibody or antibody against FAM209B could matter depends on whether native FAM209B is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

FAM209B 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 FAM209B as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/FAM209B. 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).

© 2026 · Seroatlas, Discover Oregon LLC · Terms of use

Loading the interactive Seroatlas protein explorer...