CYB5B
Cytochrome b5 type B
Also known as: CYB5-M, CYB5B_HUMAN
Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene
Protein identityUniProt · HPA
- UniProt accession
- O43169
- Gene
- CYB5B
- Ensembl
- ENSG00000103018
- Chromosome
- 16
- Canonical length
- 150 aa
- Protein class
- Plasma proteins, Predicted intracellular proteins, Predicted membrane proteins
- Subcellular location
- Endoplasmic reticulum,Centriolar satellite,Cytosol
OverviewNCBI Gene
Enables heme binding activity. Contributes to nitrite reductase (NO-forming) activity. Involved in nitric oxide biosynthetic process. Located in membrane. Part of nitric-oxide synthase complex. [provided by Alliance of Genome Resources, Jul 2025]
Canonical amino-acid sequenceUniProt
150 residues, UniProt reviewed canonical sequence.
>O43169|CYB5B
1 MSGSMATAEA SGSDGKGQEV ETSVTYYRLE EVAKRNSLKE LWLVIHGRVY DVTRFLNEHP
61 GGEEVLLEQA GVDASESFED VGHSSDAREM LKQYYIGDIH PSDLKPESGS KDPSKNDTCK
121 SCWAYWILPI IGAVLLGFLY RYYTSESKSSLocalizationUniProt · AlphaFold · HPA
Whether an antibody against CYB5B 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
- 1
- Mean surface accessibility (rSASA)
- 0.47
- Highest tissue expression
- 190 nTPM
Expression across tissuesHPA
Tissue
- adrenal gland: 190 nTPM
- rectum: 62 nTPM
- urinary bladder: 54 nTPM
- colon: 52 nTPM
- parathyroid gland: 52 nTPM
- tongue: 50 nTPM
Single-cell type
- adrenal cortex cells: 693 nCPM
- cytotrophoblasts: 219 nCPM
- gastric progenitor cells: 146 nCPM
- migrating cytotrophoblasts: 142 nCPM
- colonocytes: 129 nCPM
- tuft cells: 127 nCPM
Immune cell
- T-reg: 77 nTPM
- plasmacytoid DC: 68 nTPM
- total PBMC: 61 nTPM
- gdT-cell: 59 nTPM
- basophil: 59 nTPM
- NK-cell: 53 nTPM
Brain region
- cerebral cortex: 66 nTPM
- hypothalamus: 48 nTPM
- basal ganglia: 48 nTPM
- hippocampal formation: 48 nTPM
- amygdala: 46 nTPM
- thalamus: 44 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)
- 0.88
- gnomAD pLI
- 0.09
- gnomAD missense Z
- -0.21
- DepMap mean gene effect
- -0.32
- DepMap dependency class
- selective
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
Cellular components
Protein domainsUniProt · Pfam · InterPro
KeywordsUniProt
InteractionsUniProt · HPA
Protein binding partners of CYB5B 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 CYB5B as an antibody target. Whether an autoantibody or antibody against CYB5B could matter depends on whether native CYB5B is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.
CYB5B 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 CYB5B as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.
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