TMEM50B
Transmembrane protein 50B
Also known as: C21orf4, TM50B_HUMAN
Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene
Protein identityUniProt · HPA
- UniProt accession
- P56557
- Gene
- TMEM50B
- Ensembl
- ENSG00000142188
- Chromosome
- 21
- Canonical length
- 158 aa
- Protein class
- Predicted membrane proteins, Transporters
- Subcellular location
- Nucleoli fibrillar center
- Quaternary structure
- Homotrimer
OverviewNCBI Gene
Predicted to be involved in late endosome to vacuole transport via multivesicular body sorting pathway. Located in endoplasmic reticulum. [provided by Alliance of Genome Resources, Jul 2025]
Canonical amino-acid sequenceUniProt
158 residues, UniProt reviewed canonical sequence.
>P56557|TMEM50B
1 MAGFLDNFRW PECECIDWSE RRNAVASVVA GILFFTGWWI MIDAAVVYPK PEQLNHAFHT
61 CGVFSTLAFF MINAVSNAQV RGDSYESGCL GRTGARVWLF IGFMLMFGSL IASMWILFGA
121 YVTQNTDVYP GLAVFFQNAL IFFSTLIYKF GRTEELWTLocalizationUniProt · AlphaFold · HPA
Whether an antibody against TMEM50B 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
- Other membrane
- Secreted
- No
- Transmembrane segments
- 4
- Mean surface accessibility (rSASA)
- 0.35
- Highest tissue expression
- 84 nTPM
Expression across tissuesHPA
Tissue
- thyroid gland: 84 nTPM
- epididymis: 52 nTPM
- seminal vesicle: 46 nTPM
- kidney: 34 nTPM
- parathyroid gland: 33 nTPM
- ovary: 31 nTPM
Single-cell type
- early primary spermatocytes: 147 nCPM
- oocytes: 124 nCPM
- choroid plexus epithelial cells: 110 nCPM
- late primary spermatocytes: 91 nCPM
- esophageal apical cells: 78 nCPM
- renal collecting duct principal cells: 69 nCPM
Immune cell
- eosinophil: 44 nTPM
- T-reg: 35 nTPM
- plasmacytoid DC: 27 nTPM
- myeloid DC: 25 nTPM
- naive CD4 T-cell: 25 nTPM
- non-classical monocyte: 23 nTPM
Brain region
- choroid plexus: 41 nTPM
- thalamus: 40 nTPM
- midbrain: 37 nTPM
- amygdala: 30 nTPM
- pons: 27 nTPM
- hypothalamus: 26 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)
- 0.92
- gnomAD pLI
- 0.03
- gnomAD missense Z
- 0.88
- DepMap mean gene effect
- -0.19
- 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
Cellular components
Protein domainsUniProt · Pfam · InterPro
KeywordsUniProt
Antibody and autoantibody relevanceSeroatlas analysis
Seroatlas reads TMEM50B as an antibody target. Whether an autoantibody or antibody against TMEM50B could matter depends on whether native TMEM50B is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.
TMEM50B 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 TMEM50B as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.
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