Seroatlas · Human Serome Atlas

SPESP1

Sperm equatorial segment protein 1

Also known as: SP-ESP, SPESP_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q6UW49
Gene: SPESP1
Ensembl: ENSG00000258484
Chromosome: 15
Canonical length: 350 aa
Protein class: Predicted secreted proteins
Subcellular location: Microtubules,Cytokinetic bridge,Mitotic spindle,Acrosome,Equatorial segment
Secretome location: Secreted in male reproductive system

OverviewNCBI Gene

The encoded protein is a human alloantigen involved in sperm-egg binding and fusion. [provided by RefSeq, Apr 2010]

Canonical amino-acid sequenceUniProt

350 residues, UniProt reviewed canonical sequence.

>Q6UW49|SPESP1
     1  MKPLVLLVAL LLWPSSVPAY PSITVTPDEE QNLNHYIQVL ENLVRSVPSG EPGREKKSNS
    61  PKHVYSIASK GSKFKELVTH GDASTENDVL TNPISEETTT FPTGGFTPEI GKKKHTESTP
   121  FWSIKPNNVS IVLHAEEPYI ENEEPEPEPE PAAKQTEAPR MLPVVTESST SPYVTSYKSP
   181  VTTLDKSTGI GISTESEDVP QLSGETAIEK PEEFGKHPES WNNDDILKKI LDINSQVQQA
   241  LLSDTSNPAY REDIEASKDH LKRSLALAAA AEHKLKTMYK SQLLPVGRTS NKIDDIETVI
   301  NMLCNSRSKL YEYLDIKCVP PEMREKAATV FNTLKNMCRS RRVTALLKVY

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SPESP1 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): 0.62
Highest tissue expression: 68 nTPM

Expression across tissuesHPA

Tissue

testis: 68 nTPM
placenta: 12 nTPM
epididymis: 5.9 nTPM
parathyroid gland: 4.4 nTPM
ovary: 3.9 nTPM
spinal cord: 3.9 nTPM

Single-cell type

cardiomyocytes: 44 nCPM
late primary spermatocytes: 42 nCPM
renal collecting duct intercalated cells: 41 nCPM
ependymal cells: 39 nCPM
late spermatids: 38 nCPM
adipocytes: 36 nCPM

Immune cell

classical monocyte: 1.3 nTPM
basophil: 1.1 nTPM
intermediate monocyte: 1 nTPM
myeloid DC: 0.7 nTPM
non-classical monocyte: 0.7 nTPM
memory B-cell: 0.5 nTPM

Brain region

white matter: 1.8 nTPM
medulla oblongata: 1.4 nTPM
spinal cord: 1.3 nTPM
cerebellum: 1.2 nTPM
hypothalamus: 1.2 nTPM
pons: 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): 1.72
gnomAD pLI: 0.39
gnomAD missense Z: 0.19
DepMap mean gene effect: 0.02
DepMap dependency class: selective

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

Cellular components

Protein domainsUniProt · Pfam · InterPro

Sperm equatorial segment protein 1
Sperm equatorial segment protein 1

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SPESP1 as an antibody target. Whether an autoantibody or antibody against SPESP1 could matter depends on whether native SPESP1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SPESP1 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 SPESP1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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