Seroatlas · Human Serome Atlas

STPG1

O(6)-methylguanine-induced apoptosis 2

Also known as: C1orf201, FLJ33340, MAPO2, STPG1_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q5TH74
Gene: STPG1
Ensembl: ENSG00000001460
Chromosome: 1
Canonical length: 334 aa
Protein class: Predicted intracellular proteins
Subcellular location: Nucleoplasm

OverviewNCBI Gene

Involved in positive regulation of apoptotic process and positive regulation of mitochondrial membrane permeability involved in apoptotic process. Predicted to be located in mitochondrion and nucleus. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

334 residues, UniProt reviewed canonical sequence.

>Q5TH74|STPG1
     1  MDNSAQKNER TGKHPRRASE VQKGFTAAYP TQSSIPFKSQ ASVIPESEKK GFNSQAKRFP
    61  HKKNDIPGPG FYNVIHQSPV SNSVSLSKKG TCMFPSMCAR LDTIISKYPA ANAYTIPSDF
   121  ISKRDFSNSC SSMFQLPSFM KALKFETPAP NYYNASVSCC KQRNNVCTRA GFMSKTQRGS
   181  FAFADKGPPP GHYDINESLV KQSPNTLMSC FKSKTNRGLK LTSTGPGPGY YNPSDCTKVP
   241  KKTLFPKNPI LNFSAQPSPL PPKPPFPGPG QYEIVDYLGP RKHFISSASF VSNTSRWTAA
   301  PPQPGLPGPA TYKPELPGKQ SFLYNEDKKW IPVL

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against STPG1 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): 0.66
Highest tissue expression: 26 nTPM

Expression across tissuesHPA

Tissue

testis: 26 nTPM
fallopian tube: 16 nTPM
choroid plexus: 15 nTPM
retina: 14 nTPM
cerebellum: 12 nTPM
cerebral cortex: 11 nTPM

Single-cell type

late spermatids: 1,128 nCPM
early spermatids: 295 nCPM
late primary spermatocytes: 164 nCPM
ependymal cells: 95 nCPM
respiratory ciliated cells: 82 nCPM
choroid plexus epithelial cells: 77 nCPM

Immune cell

memory B-cell: 2.3 nTPM
memory CD8 T-cell: 2 nTPM
naive B-cell: 1.9 nTPM
plasmacytoid DC: 1.3 nTPM
T-reg: 1.2 nTPM
gdT-cell: 0.8 nTPM

Brain region

choroid plexus: 23 nTPM
cerebral cortex: 15 nTPM
thalamus: 14 nTPM
midbrain: 13 nTPM
white matter: 13 nTPM
hypothalamus: 11 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): 1.34
gnomAD pLI: 0
gnomAD missense Z: 0.25
DepMap mean gene effect: 0.06
DepMap dependency class: none

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

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads STPG1 as an antibody target. Whether an autoantibody or antibody against STPG1 could matter depends on whether native STPG1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

STPG1 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 STPG1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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