Seroatlas · Human Serome Atlas

SPEM1

Spermatid maturation protein 1

Also known as: C17orf83, FLJ40081, SPEM1_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q8N4L4
Gene: SPEM1
Ensembl: ENSG00000181323
Chromosome: 17
Canonical length: 309 aa
Protein class: Predicted membrane proteins
Subcellular location: Golgi apparatus,Calyx

OverviewNCBI Gene

Predicted to be involved in flagellated sperm motility and sperm individualization. Predicted to act upstream of or within spermatogenesis. Predicted to be located in membrane. Predicted to be active in cytoplasm. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

309 residues, UniProt reviewed canonical sequence.

>Q8N4L4|SPEM1
     1  MAMVERPRPE WASYHNCNSN SCQDLGNSVL LLLGLIICIN ISINIVTLLW SRFRGVLYQV
    61  FHDTICEKEA PKSSLLRKQT QPPKKQSSPA VHLRCTMDPV MMTVSPPPAH RHRRRGSPTR
   121  CAHCPVAWAP DTDDEKPHQY PAICSYHWDV PEDWEGFQHT QGTWVPWSQD APESPPQTIR
   181  FQPTVEERPL KTGIWSELGL RAYVYPVNPP PPSPEAPSHK NGGEGAVPEA EAAQYQPVPA
   241  PTLGPAVIPE FSRHRSSGRI VYDARDMRRR LRELTREVEA LSGCYPLASG SSTAEETSKN
   301  WVYRSLTGR

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SPEM1 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: 1
Mean surface accessibility (rSASA): 0.67
Highest tissue expression: 71 nTPM

Expression across tissuesHPA

Tissue

testis: 71 nTPM
retina: 0.1 nTPM
adipose tissue: 0 nTPM
adrenal gland: 0 nTPM
amygdala: 0 nTPM
appendix: 0 nTPM

Single-cell type

late spermatids: 3,332 nCPM
early spermatids: 390 nCPM
late primary spermatocytes: 21 nCPM
sertoli cells: 4.5 nCPM
leydig cells: 1.6 nCPM
undifferentiated spermatogonia: 0.8 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

cerebellum: 0.2 nTPM
cerebral cortex: 0.2 nTPM
hippocampal formation: 0.2 nTPM
basal ganglia: 0.1 nTPM
medulla oblongata: 0.1 nTPM
midbrain: 0.1 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): 1.26
gnomAD pLI: 0
gnomAD missense Z: 0.02
DepMap mean gene effect: 0
DepMap dependency class: none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 5% 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

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SPEM1 as an antibody target. Whether an autoantibody or antibody against SPEM1 could matter depends on whether native SPEM1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SPEM1 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 SPEM1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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