Seroatlas · Human Serome Atlas

IZUMO3

Izumo sperm-egg fusion protein 3

Also known as: bA20A20.1, C9orf134, IZUM3_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q5VZ72
Gene: IZUMO3
Ensembl: ENSG00000205442
Chromosome: 9
Canonical length: 239 aa
Protein class: Predicted membrane proteins, Transporters
Subcellular location: Acrosome,Equatorial segment
Quaternary structure: Homodimer

OverviewNCBI Gene

Predicted to enable protein homodimerization activity. Predicted to be involved in acrosome assembly. Predicted to be located in inner acrosomal membrane. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

239 residues, UniProt reviewed canonical sequence.

>Q5VZ72|IZUMO3
     1  MGDLWLFLLL PLSAFHGVKG CLECDPKFIE DVGSLLGNLI PSEVPGRTQL LERQIKEMIH
    61  LSFKVSHSDK RLRVLAVQQV VKLRTWLKNE FYKLGNETWK GVFIYQGKLL DVCQNLESKL
   121  KELLKNFSEI ACSEDCIVVE GPILDCWTCL RMTNRCFKGE YCGDEDPRKA ENREIALFLI
   181  LLATAVILGS AVLLFHFCIF HRRKMKAIRR SLKEYVEKKL EELMGKIDEK EEKDFRLRK

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against IZUMO3 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: 1
Mean surface accessibility (rSASA): 0.37
Highest tissue expression: 13 nTPM

Expression across tissuesHPA

Tissue

testis: 13 nTPM
adipose tissue: 0 nTPM
adrenal gland: 0 nTPM
amygdala: 0 nTPM
appendix: 0 nTPM
basal ganglia: 0 nTPM

Single-cell type

early spermatids: 212 nCPM
late primary spermatocytes: 189 nCPM
late spermatids: 143 nCPM
undifferentiated spermatogonia: 2.6 nCPM
sertoli cells: 1.7 nCPM
peritubular myoid cells: 1.3 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

cerebral cortex: 1.2 nTPM
pons: 0.7 nTPM
thalamus: 0.3 nTPM
white matter: 0.3 nTPM
basal ganglia: 0.2 nTPM
medulla oblongata: 0.2 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): 1.73
gnomAD pLI: 0
gnomAD missense Z: -0.23
DepMap mean gene effect: 0.17
DepMap dependency class: none

OntologyGO

Biological processes

acrosome assembly

Molecular functions

protein homodimerization activity

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads IZUMO3 as an antibody target. Whether an autoantibody or antibody against IZUMO3 could matter depends on whether native IZUMO3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

IZUMO3 is annotated at the cell surface, where native IZUMO3 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 IZUMO3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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