FAM3B
Protein FAM3B
Also known as: 2-21, C21orf11, C21orf76, D21M16SJHU19e, FAM3B_HUMAN, ORF9, PANDER, PRED44
Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene
Protein identityUniProt · HPA
- UniProt accession
- P58499
- Gene
- FAM3B
- Ensembl
- ENSG00000183844
- Chromosome
- 21
- Canonical length
- 235 aa
- Protein class
- Predicted intracellular proteins, Predicted membrane proteins, Predicted secreted proteins
- Subcellular location
- Vesicles
- Secretome location
- Secreted to blood
OverviewNCBI Gene
Predicted to enable cytokine activity. Involved in insulin secretion. Located in extracellular exosome. [provided by Alliance of Genome Resources, Jul 2025]
Canonical amino-acid sequenceUniProt
235 residues, UniProt reviewed canonical sequence.
>P58499|FAM3B
1 MRPLAGGLLK VVFVVFASLC AWYSGYLLAE LIPDAPLSSA AYSIRSIGER PVLKAPVPKR
61 QKCDHWTPCP SDTYAYRLLS GGGRSKYAKI CFEDNLLMGE QLGNVARGIN IAIVNYVTGN
121 VTATRCFDMY EGDNSGPMTK FIQSAAPKSL LFMVTYDDGS TRLNNDAKNA IEALGSKEIR
181 NMKFRSSWVF IAAKGLELPS EIQREKINHS DAKNNRYSGW PAEIQIEGCI PKERSLocalizationUniProt · AlphaFold · HPA
Whether an antibody against FAM3B 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)
- 0.34
- Highest tissue expression
- 192 nTPM
Expression across tissuesHPA
Tissue
- pancreas: 192 nTPM
- duodenum: 134 nTPM
- small intestine: 127 nTPM
- salivary gland: 112 nTPM
- stomach: 108 nTPM
- esophagus: 51 nTPM
Single-cell type
- esophageal apical cells: 809 nCPM
- enterocytes: 792 nCPM
- pancreatic acinar cells: 457 nCPM
- cytotrophoblasts: 417 nCPM
- urothelial cells: 375 nCPM
- esophageal suprabasal cells: 306 nCPM
Immune cell
- neutrophil: 2.8 nTPM
- eosinophil: 1.4 nTPM
- plasmacytoid DC: 0.6 nTPM
- memory B-cell: 0.4 nTPM
- classical monocyte: 0.3 nTPM
- non-classical monocyte: 0.3 nTPM
Brain region
- choroid plexus: 2.3 nTPM
- medulla oblongata: 0.2 nTPM
- pons: 0.2 nTPM
- thalamus: 0.2 nTPM
- cerebral cortex: 0.1 nTPM
- hypothalamus: 0.1 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)
- 1.54
- gnomAD pLI
- 0
- gnomAD missense Z
- 0.46
- DepMap mean gene effect
- 0.01
- DepMap dependency class
- selective
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 FAM3B 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 FAM3B as an antibody target. Whether an autoantibody or antibody against FAM3B could matter depends on whether native FAM3B is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.
FAM3B is annotated as secreted, so native FAM3B 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 FAM3B as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.
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