Seroatlas · Human Serome Atlas

CYB5R4

Cytochrome b5 reductase 4

Also known as: b5+b5R, dJ676J13.1, NB5R4_HUMAN, NCB5OR

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

Protein identityUniProt · HPA

UniProt accession
Q7L1T6
Gene
CYB5R4
Ensembl
ENSG00000065615
Chromosome
6
Canonical length
521 aa
Protein class
Enzymes, Metabolic proteins, Predicted intracellular proteins

OverviewNCBI Gene

This locus represents naturally occurring readthrough transcription between the neighboring RIPPLY2 (ripply transcriptional repressor 2) and CYB5R4 (cytochrome b5 reductase 4) genes on chromosome 6. Multiple readthrough transcript variants exist for this readthrough gene. One variant encodes a protein that shares sequence identity with the downstream gene product but lacks the N-terminal region and initiates translation from an in-frame, downstream start codon. Additional readthrough transcript variants are candidates for nonsense-mediated mRNA decay (NMD), and are unlikely to produce a protein product. [provided by RefSeq, Jan 2022]

Canonical amino-acid sequenceUniProt

521 residues, UniProt reviewed canonical sequence.

>Q7L1T6|CYB5R4
     1  MLNVPSQSFP APRSQQRVAS GGRSKVPLKQ GRSLMDWIRL TKSGKDLTGL KGRLIEVTEE
    61  ELKKHNKKDD CWICIRGFVY NVSPYMEYHP GGEDELMRAA GSDGTELFDQ VHRWVNYESM
   121  LKECLVGRMA IKPAVLKDYR EEEKKVLNGM LPKSQVTDTL AKEGPSYPSY DWFQTDSLVT
   181  IAIYTKQKDI NLDSIIVDHQ NDSFRAETII KDCLYLIHIG LSHEVQEDFS VRVVESVGKI
   241  EIVLQKKENT SWDFLGHPLK NHNSLIPRKD TGLYYRKCQL ISKEDVTHDT RLFCLMLPPS
   301  THLQVPIGQH VYLKLPITGT EIVKPYTPVS GSLLSEFKEP VLPNNKYIYF LIKIYPTGLF
   361  TPELDRLQIG DFVSVSSPEG NFKISKFQEL EDLFLLAAGT GFTPMVKILN YALTDIPSLR
   421  KVKLMFFNKT EDDIIWRSQL EKLAFKDKRL DVEFVLSAPI SEWNGKQGHI SPALLSEFLK
   481  RNLDKSKVLV CICGPVPFTE QGVRLLHDLN FSKNEIHSFT A

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CYB5R4 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)
0.31
Highest tissue expression
16 nTPM

Expression across tissuesHPA

Tissue

  • bone marrow: 16 nTPM
  • appendix: 11 nTPM
  • testis: 11 nTPM
  • lymph node: 9.1 nTPM
  • spleen: 8.3 nTPM
  • small intestine: 6.9 nTPM

Single-cell type

  • neutrophils: 1,022 nCPM
  • late spermatids: 652 nCPM
  • neutrophil progenitors: 287 nCPM
  • early spermatids: 287 nCPM
  • monocytes: 229 nCPM
  • microglia: 127 nCPM

Immune cell

  • neutrophil: 200 nTPM
  • eosinophil: 178 nTPM
  • basophil: 104 nTPM
  • classical monocyte: 59 nTPM
  • non-classical monocyte: 59 nTPM
  • intermediate monocyte: 51 nTPM

Brain region

  • cerebellum: 38 nTPM
  • white matter: 34 nTPM
  • cerebral cortex: 32 nTPM
  • pons: 29 nTPM
  • basal ganglia: 28 nTPM
  • medulla oblongata: 27 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)
0.94
gnomAD pLI
0
gnomAD missense Z
0.74
DepMap mean gene effect
-0.28
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% 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

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads CYB5R4 as an antibody target. Whether an autoantibody or antibody against CYB5R4 could matter depends on whether native CYB5R4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CYB5R4 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 CYB5R4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/CYB5R4. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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