Seroatlas · Human Serome Atlas

STPG3

Protein STPG3

Also known as: C9orf173, FLJ40246, STPG3_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q8N7X2
Gene: STPG3
Ensembl: ENSG00000197768
Chromosome: 9
Canonical length: 386 aa
Protein class: Predicted intracellular proteins
Subcellular location: Vesicles

OverviewNCBI Gene

Predicted to be active in cytoskeleton. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

386 residues, UniProt reviewed canonical sequence.

>Q8N7X2|STPG3
     1  MMNSDQKAVK FLANFYINGG KHWTHGHLRQ TQPEPTQPKA SVLLLGPEPG MAWDETQPPK
    61  MKEIPVGLRL QTGTPQESLP TYTQTLRELL LEQRPLITAD LEVPSPTRYQ VPSPSVRESS
   121  PHPHYSIGCK HQGREGGGRR AWQTLWFQSE SPFTQKADFD QEQKWPSPAH YQLLSRPAFP
   181  AFSFRGCHSA SKTPEGHTHL GLPGARGLGL RVQPQSLLQA SLQAPGKRCP GPNTYNILPG
   241  SRLQSPRSPA FSMSRSPAFT SWLSTSFSFG SPNPWPSRLP RGGLQLTLPF GAWRGHPGCT
   301  QTQAPRHRPL LHALEPAGHN LLGPATEWNH GLPRGFPRPP LGLGAPAWPS DPLGTPMHPS
   361  GWPTLLWAVD KAGPAWIPHL PISPLH

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against STPG3 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): 0.7
Highest tissue expression: 41 nTPM

Expression across tissuesHPA

Tissue

testis: 41 nTPM
duodenum: 3.7 nTPM
small intestine: 2.7 nTPM
liver: 1.5 nTPM
retina: 1.4 nTPM
salivary gland: 1.3 nTPM

Single-cell type

late spermatids: 2,287 nCPM
early spermatids: 377 nCPM
late primary spermatocytes: 114 nCPM
sertoli cells: 7.3 nCPM
corticotrophs: 4.4 nCPM
adipocytes: 3.1 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: 1.8 nTPM
cerebellum: 1.5 nTPM
medulla oblongata: 1.5 nTPM
hypothalamus: 1.4 nTPM
midbrain: 1.4 nTPM
pons: 1.4 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about STPG3.

Disease | ImmuneIEDB

Conditions an epitope on STPG3 was assayed in.

human immunodeficiency virus infectious disease T cell

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): 1.73
gnomAD pLI: 0
DepMap mean gene effect: 0.08
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

Cellular components

cytoskeleton

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads STPG3 as an antibody target. Whether an autoantibody or antibody against STPG3 could matter depends on whether native STPG3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

STPG3 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 STPG3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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