Seroatlas · Human Serome Atlas

FAM118B

Protein FAM118B

Also known as: F118B_HUMAN, FLJ21103

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

Protein identityUniProt · HPA

UniProt accession: Q9BPY3
Gene: FAM118B
Ensembl: ENSG00000197798
Chromosome: 11
Canonical length: 351 aa
Protein class: Predicted intracellular proteins

OverviewNCBI Gene

Enables identical protein binding activity. Predicted to be located in Cajal body. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

351 residues, UniProt reviewed canonical sequence.

>Q9BPY3|FAM118B
     1  MASTGSQASD IDEIFGFFND GEPPTKKPRK LLPSLKTKKP RELVLVIGTG ISAAVAPQVP
    61  ALKSWKGLIQ ALLDAAIDFD LLEDEESKKF QKCLHEDKNL VHVAHDLIQK LSPRTSNVRS
   121  TFFKDCLYEV FDDLESKMED SGKQLLQSVL HLMENGALVL TTNFDNLLEL YAADQGKQLE
   181  SLDLTDEKKV LEWAQEKRKL SVLHIHGVYT NPSGIVLHPA GYQNVLRNTE VMREIQKLYE
   241  NKSFLFLGCG WTVDDTTFQA LFLEAVKHKS DLEHFMLVRR GDVDEFKKLR ENMLDKGIKV
   301  ISYGDDYADL PEYFKRLTCE ISTRGTSAGM VREGQLNGSS AAHSEIRGCS T

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against FAM118B 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: 0
Mean surface accessibility (rSASA): 0.32
Highest tissue expression: 29 nTPM

Expression across tissuesHPA

Tissue

choroid plexus: 29 nTPM
basal ganglia: 23 nTPM
colon: 23 nTPM
rectum: 22 nTPM
skeletal muscle: 22 nTPM
testis: 20 nTPM

Single-cell type

pituicytes/fscs: 82 nCPM
late primary spermatocytes: 72 nCPM
myonuclei: 59 nCPM
choroid plexus epithelial cells: 55 nCPM
cardiomyocytes: 50 nCPM
hofbauer cells: 49 nCPM

Immune cell

non-classical monocyte: 60 nTPM
intermediate monocyte: 59 nTPM
myeloid DC: 48 nTPM
classical monocyte: 44 nTPM
basophil: 34 nTPM
total PBMC: 25 nTPM

Brain region

choroid plexus: 24 nTPM
basal ganglia: 22 nTPM
white matter: 16 nTPM
hypothalamus: 15 nTPM
spinal cord: 15 nTPM
cerebral cortex: 15 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): 0.68
gnomAD pLI: 0.02
gnomAD missense Z: 0.96
DepMap mean gene effect: 0.17
DepMap dependency class: none

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

Molecular functions

identical protein binding

Cellular components

Cajal body

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads FAM118B as an antibody target. Whether an autoantibody or antibody against FAM118B could matter depends on whether native FAM118B is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

FAM118B 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 FAM118B as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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