Seroatlas · Human Serome Atlas

FAM133B

Protein FAM133B

Also known as: F133B_HUMAN, MGC40405

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

Protein identityUniProt · HPA

UniProt accession: Q5BKY9
Gene: FAM133B
Ensembl: ENSG00000234545
Chromosome: 7
Canonical length: 247 aa
Protein class: Predicted intracellular proteins
Subcellular location: Nucleoplasm,Nucleoli

OverviewNCBI Gene

Enables RNA binding activity. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

247 residues, UniProt reviewed canonical sequence.

>Q5BKY9|FAM133B
     1  MGKRDNRVAY MNPIAMARSR GPIQSSGPTI QDYLNRPRPT WEEVKEQLEK KKKGSKALAE
    61  FEEKMNENWK KELEKHREKL LSGSESSSKK RQRKKKEKKK SGRYSSSSSS SSDSSSSSSD
   121  SEDEDKKQGK RRKKKKNRSH KSSESSMSET ESDSKDSLKK KKKSKDGTEK EKDIKGLSKK
   181  RKMYSEDKPL SSESLSESEY IEEVRAKKKK SSEEREKATE KTKKKKKHKK HSKKKKKKAA
   241  SSSPDSP

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against FAM133B 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: Unknown
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.66
Highest tissue expression: 33 nTPM

Expression across tissuesHPA

Tissue

bone marrow: 33 nTPM
cerebellum: 21 nTPM
epididymis: 21 nTPM
thymus: 16 nTPM
lymph node: 16 nTPM
breast: 15 nTPM

Single-cell type

epididymal principal cells: 188 nCPM
erythrocyte progenitors: 168 nCPM
pituicytes/fscs: 132 nCPM
epididymal efferent duct absorptive cells: 131 nCPM
tuft cells: 127 nCPM
endometrial glandular cells: 124 nCPM

Immune cell

plasmacytoid DC: 31 nTPM
memory B-cell: 30 nTPM
naive B-cell: 23 nTPM
T-reg: 21 nTPM
naive CD4 T-cell: 20 nTPM
MAIT T-cell: 19 nTPM

Brain region

white matter: 31 nTPM
cerebellum: 30 nTPM
cerebral cortex: 28 nTPM
basal ganglia: 25 nTPM
thalamus: 25 nTPM
pons: 25 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): 0.83
gnomAD pLI: 0
gnomAD missense Z: 0.89
DepMap mean gene effect: -0.83
DepMap dependency class: common

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 8% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Molecular functions

RNA binding

Protein domainsUniProt · Pfam · InterPro

Protein FAM133

KeywordsUniProt

Phosphoprotein

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads FAM133B as an antibody target. Whether an autoantibody or antibody against FAM133B could matter depends on whether native FAM133B is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

FAM133B 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 FAM133B as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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