Seroatlas · Human Serome Atlas

SRD5A1

3-oxo-5-alpha-steroid 4-dehydrogenase 1

Also known as: S5A1_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P18405
Gene
SRD5A1
Ensembl
ENSG00000145545
Chromosome
5
Canonical length
259 aa
Protein class
Cancer-related genes, Enzymes, FDA approved drug targets, Metabolic proteins, Predicted membrane proteins

OverviewNCBI Gene

Steroid 5-alpha-reductase (EC 1.3.99.5) catalyzes the conversion of testosterone into the more potent androgen, dihydrotestosterone (DHT). Also see SRD5A2 (MIM 607306).[supplied by OMIM, Mar 2008]

Canonical amino-acid sequenceUniProt

259 residues, UniProt reviewed canonical sequence.

>P18405|SRD5A1
     1  MATATGVAEE RLLAALAYLQ CAVGCAVFAR NRQTNSVYGR HALPSHRLRV PARAAWVVQE
    61  LPSLALPLYQ YASESAPRLR SAPNCILLAM FLVHYGHRCL IYPFLMRGGK PMPLLACTMA
   121  IMFCTCNGYL QSRYLSHCAV YADDWVTDPR FLIGFGLWLT GMLINIHSDH ILRNLRKPGD
   181  TGYKIPRGGL FEYVTAANYF GEIMEWCGYA LASWSVQGAA FAFFTFCFLS GRAKEHHEWY
   241  LRKFEEYPKF RKIIIPFLF

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SRD5A1 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
Other membrane
Secreted
No
Transmembrane segments
5
Mean surface accessibility (rSASA)
0.27
Highest tissue expression
27 nTPM

Expression across tissuesHPA

Tissue

  • liver: 27 nTPM
  • skin: 13 nTPM
  • esophagus: 11 nTPM
  • breast: 10 nTPM
  • cerebral cortex: 7 nTPM
  • vagina: 6.5 nTPM

Single-cell type

  • esophageal basal cells: 186 nCPM
  • hepatocytes: 170 nCPM
  • esophageal suprabasal cells: 163 nCPM
  • suprabasal keratinocytes: 117 nCPM
  • basal keratinocytes: 82 nCPM
  • distal convoluted tubule cells: 60 nCPM

Immune cell

  • basophil: 3.4 nTPM
  • myeloid DC: 1.6 nTPM
  • classical monocyte: 1.3 nTPM
  • non-classical monocyte: 1.1 nTPM
  • intermediate monocyte: 1 nTPM
  • plasmacytoid DC: 0.7 nTPM

Brain region

  • cerebral cortex: 38 nTPM
  • white matter: 37 nTPM
  • cerebellum: 36 nTPM
  • thalamus: 36 nTPM
  • pons: 35 nTPM
  • medulla oblongata: 33 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)
1.29
gnomAD pLI
0
gnomAD missense Z
0.59
DepMap mean gene effect
0.07
DepMap dependency class
none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 9% 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

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SRD5A1 as an antibody target. Whether an autoantibody or antibody against SRD5A1 could matter depends on whether native SRD5A1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SRD5A1 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 SRD5A1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/SRD5A1. 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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