Seroatlas · Human Serome Atlas

SMIM40

Small integral membrane protein 40

Also known as: SIM40_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q5STR5
Gene
SMIM40
Ensembl
ENSG00000286920
Chromosome
6
Canonical length
79 aa
Protein class
Predicted membrane proteins

OverviewNCBI Gene

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

Canonical amino-acid sequenceUniProt

79 residues, UniProt reviewed canonical sequence.

>Q5STR5|SMIM40
     1  MAEEGDVDEA DVFLAFAQGP SPPRGPVRRA LDKAFFIFLA LFLTLLMLEA AYKLLWLLLW
    61  AKLGDWLLGT PQKEEELEL

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SMIM40 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
Unknown
Secreted
No
Transmembrane segments
1
Mean surface accessibility (rSASA)
0.56
Highest tissue expression
43 nTPM

Expression across tissuesHPA

Tissue

  • retina: 43 nTPM
  • testis: 0.1 nTPM
  • adipose tissue: 0 nTPM
  • adrenal gland: 0 nTPM
  • amygdala: 0 nTPM
  • appendix: 0 nTPM

Single-cell type

  • rod photoreceptor cells: 35 nCPM
  • late primary spermatocytes: 2.5 nCPM
  • müller glia: 1.9 nCPM
  • retinal bipolar cells: 1.5 nCPM
  • plasma cells: 0.5 nCPM
  • early spermatids: 0.3 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

  • amygdala: 0 nTPM
  • basal ganglia: 0 nTPM
  • cerebellum: 0 nTPM
  • cerebral cortex: 0 nTPM
  • choroid plexus: 0 nTPM
  • hippocampal formation: 0 nTPM

OntologyGO

Cellular components

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SMIM40 as an antibody target. Whether an autoantibody or antibody against SMIM40 could matter depends on whether native SMIM40 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SMIM40 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 SMIM40 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/SMIM40. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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