Seroatlas · Human Serome Atlas

SPANXA1

Sperm protein associated with the nucleus on the X chromosome A

Also known as: CT11.1, NAP-X, SPAN-Xa, SPAN-Xb, SPANX, SPANXA2, SPNXA_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q9NS26
Gene: SPANXA1
Ensembl: ENSG00000198021
Chromosome: X
Canonical length: 97 aa
Protein class: Predicted intracellular proteins
Subcellular location: Nucleoplasm,Vesicles

OverviewNCBI Gene

Temporally regulated transcription and translation of several testis-specific genes is required to initiate the series of molecular and morphological changes in the male germ cell lineage necessary for the formation of mature spermatozoa. This gene is a member of the SPANX family of cancer/testis-associated genes, which are located in a cluster on chromosome X. The SPANX genes encode differentially expressed testis-specific proteins that localize to various subcellular compartments. This particular gene maps to chromosome X in a head-to-head orientation with SPANX family member A2, which appears to be a duplication of the A1 locus. The protein encoded by this gene targets to the nucleus where it associates with nuclear vacuoles and the redundant nuclear envelope. Based on its association with these poorly characterized regions of the sperm nucleus, this protein provides a biochemical marker to study unique structures in spermatazoa while attempting to further define its role in spermatogenesis. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

97 residues, UniProt reviewed canonical sequence.

>Q9NS26|SPANXA1
     1  MDKQSSAGGV KRSVPCDSNE ANEMMPETPT GDSDPQPAPK KMKTSESSTI LVVRYRRNFK
    61  RTSPEELLND HARENRINPL QMEEEEFMEI MVEIPAK

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SPANXA1 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): 0.63
Highest tissue expression: 4.3 nTPM

Expression across tissuesHPA

Tissue

testis: 4.3 nTPM
adipose tissue: 0 nTPM
adrenal gland: 0 nTPM
amygdala: 0 nTPM
appendix: 0 nTPM
basal ganglia: 0 nTPM

Single-cell type

adipocytes: 0 nCPM
adrenal cortex cells: 0 nCPM
adrenal medulla cells: 0 nCPM
alveolar cells type 1: 0 nCPM
alveolar cells type 2: 0 nCPM
astrocytes: 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

cerebral cortex: 3.4 nTPM
pons: 2 nTPM
white matter: 1.8 nTPM
thalamus: 1.7 nTPM
medulla oblongata: 1.6 nTPM
midbrain: 1.5 nTPM

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 0% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

spermatogenesis

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SPANXA1 as an antibody target. Whether an autoantibody or antibody against SPANXA1 could matter depends on whether native SPANXA1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SPANXA1 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 SPANXA1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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