Seroatlas · Human Serome Atlas

OPN4

Melanopsin

Also known as: melanopsin, MOP, OPN4_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q9UHM6
Gene
OPN4
Ensembl
ENSG00000122375
Chromosome
10
Canonical length
478 aa
Protein class
G-protein coupled receptors, Predicted membrane proteins, Transporters

OverviewNCBI Gene

Opsins are members of the guanine nucleotide-binding protein (G protein)-coupled receptor superfamily. This gene encodes a photoreceptive opsin protein that is expressed within the ganglion and amacrine cell layers of the retina. In mouse, retinal ganglion cell axons expressing this gene projected to the suprachiasmatic nucleus and other brain nuclei involved in circadian photoentrainment. In mouse, this protein is coupled to a transient receptor potential (TRP) ion channel through a G protein signaling pathway and produces a physiologic light response via membrane depolarization and increased intracellular calcium. The protein functions as a sensory photopigment and may also have photoisomerase activity. Experiments with knockout mice indicate that this gene attenuates, but does not abolish, photoentrainment. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

478 residues, UniProt reviewed canonical sequence.

>Q9UHM6|OPN4
     1  MNPPSGPRVP PSPTQEPSCM ATPAPPSWWD SSQSSISSLG RLPSISPTAP GTWAAAWVPL
    61  PTVDVPDHAH YTLGTVILLV GLTGMLGNLT VIYTFCRSRS LRTPANMFII NLAVSDFLMS
   121  FTQAPVFFTS SLYKQWLFGE TGCEFYAFCG ALFGISSMIT LTAIALDRYL VITRPLATFG
   181  VASKRRAAFV LLGVWLYALA WSLPPFFGWS AYVPEGLLTS CSWDYMSFTP AVRAYTMLLC
   241  CFVFFLPLLI IIYCYIFIFR AIRETGRALQ TFGACKGNGE SLWQRQRLQS ECKMAKIMLL
   301  VILLFVLSWA PYSAVALVAF AGYAHVLTPY MSSVPAVIAK ASAIHNPIIY AITHPKYRVA
   361  IAQHLPCLGV LLGVSRRHSR PYPSYRSTHR STLTSHTSNL SWISIRRRQE SLGSESEVGW
   421  THMEAAAVWG AAQQANGRSL YGQGLEDLEA KAPPRPQGHE AETPGKTKGL IPSQDPRM

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against OPN4 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
Cell surface
Secreted
No
Transmembrane segments
7
Mean surface accessibility (rSASA)
0.41
Highest tissue expression
1.4 nTPM

Expression across tissuesHPA

Tissue

  • skeletal muscle: 1.4 nTPM
  • adipose tissue: 1.2 nTPM
  • basal ganglia: 1.1 nTPM
  • retina: 0.8 nTPM
  • cerebral cortex: 0.7 nTPM
  • thyroid gland: 0.5 nTPM

Single-cell type

  • brain inhibitory neurons: 9.7 nCPM
  • brain excitatory neurons: 3.2 nCPM
  • oligodendrocytes: 0.8 nCPM
  • other brain neurons: 0.2 nCPM
  • pericytes: 0.1 nCPM
  • adipocytes: 0 nCPM

Immune cell

  • basophil: 0 nTPM
  • classical monocyte: 0 nTPM
  • eosinophil: 0 nTPM
  • gdT-cell: 0 nTPM
  • intermediate monocyte: 0 nTPM
  • MAIT T-cell: 0 nTPM

Brain region

  • basal ganglia: 6.4 nTPM
  • cerebral cortex: 6.1 nTPM
  • white matter: 2.6 nTPM
  • hippocampal formation: 2.5 nTPM
  • amygdala: 2.3 nTPM
  • thalamus: 1.2 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)
1.29
gnomAD pLI
0
gnomAD missense Z
-0.48
DepMap mean gene effect
-0.06
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

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads OPN4 as an antibody target. Whether an autoantibody or antibody against OPN4 could matter depends on whether native OPN4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

OPN4 is annotated at the cell surface, where native OPN4 is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label OPN4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/OPN4. 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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