IZUMO4
Izumo sperm-egg fusion protein 4
Also known as: C19orf36, IZUM4_HUMAN
Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene
Protein identityUniProt · HPA
- UniProt accession
- Q1ZYL8
- Gene
- IZUMO4
- Ensembl
- ENSG00000099840
- Chromosome
- 19
- Canonical length
- 232 aa
- Protein class
- Predicted intracellular proteins, Predicted secreted proteins, Transporters
- Subcellular location
- Equatorial segment,Calyx,Connecting piece
- Secretome location
- Secreted in male reproductive system
OverviewNCBI Gene
Located in nucleus. [provided by Alliance of Genome Resources, Jul 2025]
Canonical amino-acid sequenceUniProt
232 residues, UniProt reviewed canonical sequence.
>Q1ZYL8|IZUMO4
1 MALLLCLVCL TAALAHGCLH CHSNFSKKFS FYRHHVNFKS WWVGDIPVSG ALLTDWSDDT
61 MKELHLAIPA KITREKLDQV ATAVYQMMDQ LYQGKMYFPG YFPNELRNIF REQVHLIQNA
121 IIESRIDCQH RCGIFQYETI SCNNCTDSHV ACFGYNCESS AQWKSAVQGL LNYINNWHKQ
181 DTSMRPRSSA FSWPGTHRAT PAFLVSPALR CLEPPHLANL TLEDAAECLK QHLocalizationUniProt · AlphaFold · HPA
Whether an antibody against IZUMO4 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
- Secreted
- Secreted
- Yes
- Transmembrane segments
- 0
- Mean surface accessibility (rSASA)
- 0.33
- Highest tissue expression
- 430 nTPM
Expression across tissuesHPA
Tissue
- testis: 430 nTPM
- amygdala: 19 nTPM
- spinal cord: 17 nTPM
- cerebral cortex: 17 nTPM
- basal ganglia: 16 nTPM
- midbrain: 15 nTPM
Single-cell type
- late spermatids: 4,017 nCPM
- late primary spermatocytes: 2,332 nCPM
- early spermatids: 1,650 nCPM
- early primary spermatocytes: 125 nCPM
- bergmann glia: 56 nCPM
- astrocytes: 43 nCPM
Immune cell
- memory B-cell: 2.7 nTPM
- T-reg: 2.2 nTPM
- memory CD4 T-cell: 2.1 nTPM
- naive CD4 T-cell: 1.7 nTPM
- memory CD8 T-cell: 1.6 nTPM
- neutrophil: 1.6 nTPM
Brain region
- midbrain: 10 nTPM
- thalamus: 9.6 nTPM
- white matter: 9.6 nTPM
- basal ganglia: 9 nTPM
- amygdala: 8.7 nTPM
- cerebellum: 8.6 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)
- 1.71
- gnomAD pLI
- 0
- gnomAD missense Z
- -0.89
- DepMap mean gene effect
- -0.03
- 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
Cellular components
Protein domainsUniProt · Pfam · InterPro
- Izumo sperm-egg fusion protein
- Izumo sperm-egg fusion, Ig domain-associated
- Izumo sperm-egg fusion
KeywordsUniProt
Antibody and autoantibody relevanceSeroatlas analysis
Seroatlas reads IZUMO4 as an antibody target. Whether an autoantibody or antibody against IZUMO4 could matter depends on whether native IZUMO4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.
IZUMO4 is annotated as secreted, so native IZUMO4 circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.
Annotation status
The present source text does not explicitly label IZUMO4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.
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