Seroatlas · Human Serome Atlas

SMPDL3B

Acid sphingomyelinase-like phosphodiesterase 3b

Also known as: ASM3B_HUMAN, ASML3B

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

Protein identityUniProt · HPA

UniProt accession
Q92485
Gene
SMPDL3B
Ensembl
ENSG00000130768
Chromosome
1
Canonical length
455 aa
Protein class
Predicted secreted proteins
Subcellular location
Golgi apparatus,Cytosol
Secretome location
Secreted to blood

OverviewNCBI Gene

Enables phosphoric diester hydrolase activity. Predicted to be involved in membrane lipid catabolic process; negative regulation of inflammatory response; and negative regulation of toll-like receptor signaling pathway. Located in extracellular exosome. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

455 residues, UniProt reviewed canonical sequence.

>Q92485|SMPDL3B
     1  MRLLAWLIFL ANWGGARAEP GKFWHIADLH LDPDYKVSKD PFQVCPSAGS QPVPDAGPWG
    61  DYLCDSPWAL INSSIYAMKE IEPEPDFILW TGDDTPHVPD EKLGEAAVLE IVERLTKLIR
   121  EVFPDTKVYA ALGNHDFHPK NQFPAGSNNI YNQIAELWKP WLSNESIALF KKGAFYCEKL
   181  PGPSGAGRIV VLNTNLYYTS NALTADMADP GQQFQWLEDV LTDASKAGDM VYIVGHVPPG
   241  FFEKTQNKAW FREGFNEKYL KVVRKHHRVI AGQFFGHHHT DSFRMLYDDA GVPISAMFIT
   301  PGVTPWKTTL PGVVNGANNP AIRVFEYDRA TLSLKDMVTY FMNLSQANAQ GTPRWELEYQ
   361  LTEAYGVPDA SAHSMHTVLD RIAGDQSTLQ RYYVYNSVSY SAGVCDEACS MQHVCAMRQV
   421  DIDAYTTCLY ASGTTPVPQL PLLLMALLGL CTLVL

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SMPDL3B 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
Cell surface
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.25
Highest tissue expression
47 nTPM

Expression across tissuesHPA

Tissue

  • pancreas: 47 nTPM
  • duodenum: 23 nTPM
  • rectum: 22 nTPM
  • colon: 21 nTPM
  • stomach: 16 nTPM
  • epididymis: 15 nTPM

Single-cell type

  • breast lactating cells: 103 nCPM
  • neutrophils: 87 nCPM
  • colonocytes: 58 nCPM
  • pancreatic acinar cells: 58 nCPM
  • enterocytes: 45 nCPM
  • enteric transient amplifying cells: 44 nCPM

Immune cell

  • eosinophil: 3.3 nTPM
  • neutrophil: 1.7 nTPM
  • myeloid DC: 1.3 nTPM
  • NK-cell: 0.3 nTPM
  • memory B-cell: 0.2 nTPM
  • basophil: 0.1 nTPM

Brain region

  • cerebellum: 5.8 nTPM
  • choroid plexus: 4.8 nTPM
  • cerebral cortex: 2.8 nTPM
  • thalamus: 2.2 nTPM
  • hypothalamus: 2 nTPM
  • white matter: 2 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)
1.27
gnomAD pLI
0
gnomAD missense Z
0.69
DepMap mean gene effect
0.07
DepMap dependency class
selective

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

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of SMPDL3B in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads SMPDL3B as an antibody target. Whether an autoantibody or antibody against SMPDL3B could matter depends on whether native SMPDL3B is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SMPDL3B is annotated at the cell surface, where native SMPDL3B is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label SMPDL3B as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/SMPDL3B. 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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