Seroatlas · Human Serome Atlas

SPATA21

Spermatogenesis-associated protein 21

Also known as: spergen-2, spergen2, SPT21_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q7Z572
Gene: SPATA21
Ensembl: ENSG00000187144
Chromosome: 1
Canonical length: 469 aa
Protein class: Predicted intracellular proteins
Subcellular location: Vesicles,Cytosol

OverviewNCBI Gene

Predicted to enable calcium ion binding activity. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

469 residues, UniProt reviewed canonical sequence.

>Q7Z572|SPATA21
     1  MDNRNTQMYT EEEKTVNPFL PSTPGPKKAK GGGEAVETHP APGPLPPPEV RDIGERREPD
    61  RAQQQPQKPA VAAGTQSLGN FRQGFMKCLL EVEKMEASHR RASKARSQTA QKSPRTLTPV
   121  PTSAPSLPQT PASVPASGPS WARLPAPGPE PAPMGAPVPT SMPCPVLLGP ALDLGWRRME
   181  LLHQSSERTL SYAKARQEPE EQSLQKLYQN REKSEEQLTL KQEEAFRSYF EIFNGPGEVD
   241  AQSLKNILLL MGFSVTLAQV EDALMSADVN GDGRVDFKDF LAVMTDTRRF FCSVEQNALS
   301  DMAPHNPHTL LFEILSLLVE MLALPEAVLE EITNYYQKKL KEGTCKAQEM EAAVGRLRLQ
   361  KLPYNPQQEE SSEVPERKVL SILSRLKQQN YAPNLQSPYA QVPCILLCPQ LDKKMVRRQP
   421  SNHYALDQCT PPGLDPDIRS PFFQSGSQGN REHNSDSRKW LSSVPARTH

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SPATA21 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: Unknown
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.54
Highest tissue expression: 7.3 nTPM

Expression across tissuesHPA

Tissue

testis: 7.3 nTPM
retina: 0.8 nTPM
cerebellum: 0.7 nTPM
bone marrow: 0.5 nTPM
pancreas: 0.4 nTPM
duodenum: 0.3 nTPM

Single-cell type

epicardial cells: 123 nCPM
early spermatids: 109 nCPM
late spermatids: 66 nCPM
cardiomyocytes: 58 nCPM
late primary spermatocytes: 57 nCPM
platelets: 24 nCPM

Immune cell

basophil: 1.7 nTPM
neutrophil: 0.6 nTPM
memory B-cell: 0.4 nTPM
eosinophil: 0.3 nTPM
naive B-cell: 0.3 nTPM
gdT-cell: 0.2 nTPM

Brain region

cerebellum: 6.6 nTPM
cerebral cortex: 4 nTPM
choroid plexus: 3.9 nTPM
hippocampal formation: 3.5 nTPM
white matter: 3.5 nTPM
basal ganglia: 3.4 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): 1.5
gnomAD pLI: 0
gnomAD missense Z: -0.01
DepMap mean gene effect: -0.11
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 2% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Molecular functions

calcium ion binding

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SPATA21 as an antibody target. Whether an autoantibody or antibody against SPATA21 could matter depends on whether native SPATA21 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SPATA21 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 SPATA21 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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