Seroatlas · Human Serome Atlas

SPEF1

Sperm flagellar protein 1

Also known as: C20orf28, CLAMP, DKFZP434I114, SPEF1_HUMAN, SPEF1A

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

Protein identityUniProt · HPA

UniProt accession: Q9Y4P9
Gene: SPEF1
Ensembl: ENSG00000101222
Chromosome: 20
Canonical length: 236 aa
Protein class: Predicted intracellular proteins
Quaternary structure: Homodimer

OverviewNCBI Gene

Enables actin binding activity. Involved in filopodium assembly and lamellipodium assembly. Located in several cellular components, including basolateral plasma membrane; lamellipodium; and microvillus. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

236 residues, UniProt reviewed canonical sequence.

>Q9Y4P9|SPEF1
     1  MASSVDEEAL HQLYLWVDNI PLSRPKRNLS RDFSDGVLVA EVIKFYFPKM VEMHNYVPAN
    61  SLQQKLSNWG HLNRKVLKRL NFSVPDDVMR KIAQCAPGVV ELVLIPLRQR LEERQRRRKQ
   121  GAGSLQELAP QDGSGYMDVG VSQKARGEGV PDPQGGGQLS WDRPPAPRPP AYNRALQGDP
   181  SFVLQIAEKE QELLASQETV QVLQMKVRRL EHLLQLKNVR IEDLSRRLQQ AERKQR

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SPEF1 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: 0
Mean surface accessibility (rSASA): 0.45
Highest tissue expression: 28 nTPM

Expression across tissuesHPA

Tissue

basal ganglia: 28 nTPM
choroid plexus: 24 nTPM
hippocampal formation: 14 nTPM
testis: 12 nTPM
fallopian tube: 9.3 nTPM
cerebral cortex: 8.2 nTPM

Single-cell type

epididymal efferent duct ciliated cells: 214 nCPM
respiratory ciliated cells: 166 nCPM
fallopian tube ciliated cells: 165 nCPM
endometrial ciliated cells: 118 nCPM
ependymal cells: 87 nCPM
brain inhibitory neurons: 37 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

choroid plexus: 31 nTPM
basal ganglia: 17 nTPM
midbrain: 16 nTPM
medulla oblongata: 14 nTPM
spinal cord: 12 nTPM
hippocampal formation: 8.7 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): 1.23
gnomAD pLI: 0
gnomAD missense Z: 1.17
DepMap mean gene effect: -0.15
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

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of SPEF1 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SPEF1 as an antibody target. Whether an autoantibody or antibody against SPEF1 could matter depends on whether native SPEF1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SPEF1 is annotated at the cell surface, where native SPEF1 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 SPEF1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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