Seroatlas · Human Serome Atlas

FAM13B

Protein FAM13B

Also known as: ARHGAP49, C5orf5, FA13B_HUMAN, FAM13B1, KHCHP, N61

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

Protein identityUniProt · HPA

UniProt accession: Q9NYF5
Gene: FAM13B
Ensembl: ENSG00000031003
Chromosome: 5
Canonical length: 915 aa
Protein class: Predicted intracellular proteins
Subcellular location: Nucleoplasm

OverviewNCBI Gene

Predicted to enable GTPase activator activity. Predicted to be involved in regulation of small GTPase mediated signal transduction. Predicted to be located in cytosol. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

915 residues, UniProt reviewed canonical sequence.

>Q9NYF5|FAM13B
     1  MRKSSSPSLS NCNSVLANKI FGIPLDELQQ GGHPDNEVPF IVRHVVDYIE EHGGLEQQGL
    61  FQVNGNAETV EWLRQRYDSG EEVDLVKEAD VPSAISLLRF FLQELPEPVI PGSLHIHLMQ
   121  LSQDYNNEDE FGRKLRFLLQ QLPPVNYSLL KFLCRFLANV ASHHEEIWSA NSLAAVFGPD
   181  VFHIYTDVED MKEQEIVSRI MAGLLENYYE FFENEEEDFS SNDLSSITEQ VNELSEEEEE
   241  DEKLEHIEEL PEEGAEKSND MPEVVQLRMT ENILESNSVT ATSTHISPIS ILPASTDILE
   301  RTIRAAVEQH LFDLQSSIDH DLKNLQQQSV VCNNEAESIH CDGEGSNNQI DIADDIINAS
   361  ESNRDCSKPV ASTNLDNEAM QQDCVFENEE NTQSVGILLE PCSDRGDSED GCLEREEYLL
   421  FDSDKLSHLI LDSSSKICDL NANTESEVPG GQSVGVQGEA ACVSIPHLDL KNVSDGDKWE
   481  EPFPAFKSWQ EDSESGEAQL SPQAGRMNHH PLEEDCPPVL SHRSLDFGQS QRFLHDPEKL
   541  DSSSKALSFT RIRRSSFSSK DEKREDRTPY QLVKKLQKKI RQFEEQFERE RNSKPSYSDI
   601  AANPKVLKWM TELTKLRKQI KDAKHKNSDG EFVPQTRPRS NTLPKSFGSS LDHEDEENED
   661  EPKVIQKEKK PSKEATLELI LKRLKEKRIE RCLPEDIKKM TKDHLVEEKA SLQKSLLYYE
   721  SQHGRPVTKE ERHIVKPLYD RYRLVKQMLT RASITPVLGS PSTKRRGQML QPIIEGETAH
   781  FFEEIKEEEE DGVNLSSELG DMLKTAVQVQ SSLENSESDV EENQEKLALD LRLSSSRAAS
   841  MPELLEQLWK ARAEKKKLRK TLREFEEAFY QQNGRNAQKE DRVPVLEEYR EYKKIKAKLR
   901  LLEVLISKQD SSKSI

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against FAM13B 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): 0.51
Highest tissue expression: 32 nTPM

Expression across tissuesHPA

Tissue

seminal vesicle: 32 nTPM
testis: 31 nTPM
smooth muscle: 29 nTPM
bone marrow: 23 nTPM
prostate: 22 nTPM
tonsil: 22 nTPM

Single-cell type

sertoli cells: 486 nCPM
neutrophils: 481 nCPM
neutrophil progenitors: 355 nCPM
adrenal cortex cells: 338 nCPM
oligodendrocytes: 314 nCPM
podocytes: 275 nCPM

Immune cell

basophil: 11 nTPM
eosinophil: 8.6 nTPM
neutrophil: 7.1 nTPM
NK-cell: 5.9 nTPM
non-classical monocyte: 5.7 nTPM
naive B-cell: 5.5 nTPM

Brain region

hypothalamus: 74 nTPM
cerebellum: 68 nTPM
white matter: 67 nTPM
basal ganglia: 66 nTPM
pons: 62 nTPM
cerebral cortex: 61 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): 0.37
gnomAD pLI: 0.49
gnomAD missense Z: 0.86
DepMap mean gene effect: 0.01
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

Biological processes

Molecular functions

GTPase activator activity

Cellular components

cytosol

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

GTPase activation

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads FAM13B as an antibody target. Whether an autoantibody or antibody against FAM13B could matter depends on whether native FAM13B is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

FAM13B 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 FAM13B as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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