Seroatlas · Human Serome Atlas

SMTN

Smoothelin

Also known as: SMTN_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P53814
Gene
SMTN
Ensembl
ENSG00000183963
Chromosome
22
Canonical length
917 aa
Protein class
Plasma proteins, Predicted intracellular proteins
Subcellular location
Nucleoplasm,Actin filaments

OverviewNCBI Gene

This gene encodes a structural protein that is found exclusively in contractile smooth muscle cells. It associates with stress fibers and constitutes part of the cytoskeleton. This gene is localized to chromosome 22q12.3, distal to the TUPLE1 locus and outside the DiGeorge syndrome deletion. Alternative splicing of this gene results in multiple transcript variants encoding distinct isoforms. [provided by RefSeq, May 2011]

Canonical amino-acid sequenceUniProt

917 residues, UniProt reviewed canonical sequence.

>P53814|SMTN
     1  MADEALAGLD EGALRKLLEV TADLAERRRI RSAIRELQRQ ELEREEEALA SKRFRAERQD
    61  NKENWLHSQQ REAEQRAALA RLAGQLESMN DVEELTALLR SAGEYEERKL IRAAIRRVRA
   121  QEIEAATLAG RLYSGRPNSG SREDSKGLAA HRLEQCEVPE REEQEQQAEV SKPTPTPEGT
   181  SQDVTTVTLL LRAPPGSTSS SPASPSSSPT PASPEPPLEP AEAQCLTAEV PGSPEPPPSP
   241  PKTTSPEPQE SPTLPSTEGQ VVNKLLSGPK ETPAAQSPTR GPSDTKRADV AGPRPCQRSL
   301  SVLSPRQPAQ NRESTPLASG PSSFQRAGSV RDRVHKFTSD SPMAARLQDG TPQAALSPLT
   361  PARLLGPSLT STTPASSSSG SSSRGPSDTS SRFSKEQRGV AQPLAQLRSC PQEEGPRGRG
   421  LAARPLENRA GGPVARSEEP GAPLPVAVGT AEPGGSMKTT FTIEIKDGRG QASTGRVLLP
   481  TGNQRAELTL GLRAPPTLLS TSSGGKSTIT RVNSPGTLAR LGSVTHVTSF SHAPPSSRGG
   541  CSIKMEAEPA EPLAAAVEAA NGAEQTRVNK APEGRSPLSA EELMTIEDEG VLDKMLDQST
   601  DFEERKLIRA ALRELRQRKR DQRDKERERR LQEARGRPGE GRGNTATETT TRHSQRAADG
   661  SAVSTVTKTE RLVHSNDGTR TARTTTVESS FVRRSENGSG STMMQTKTFS SSSSSKKMGS
   721  IFDREDQASP RAGSLAALEK RQAEKKKELM KAQSLPKTSA SQARKAMIEK LEKEGAAGSP
   781  GGPRAAVQRS TSFGVPNANS IKQMLLDWCR AKTRGYEHVD IQNFSSSWSD GMAFCALVHN
   841  FFPEAFDYGQ LSPQNRRQNF EVAFSSAEML VDCVPLVEVD DMMIMGKKPD PKCVFTYVQS
   901  LYNHLRRHEL RLRGKNV

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SMTN 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)
0.57
Highest tissue expression
828 nTPM

Expression across tissuesHPA

Tissue

  • colon: 828 nTPM
  • urinary bladder: 511 nTPM
  • blood vessel: 442 nTPM
  • endometrium: 238 nTPM
  • stomach: 215 nTPM
  • seminal vesicle: 157 nTPM

Single-cell type

  • smooth muscle cells: 1,281 nCPM
  • bergmann glia: 255 nCPM
  • tuft cells: 219 nCPM
  • vascular smooth muscle cells: 191 nCPM
  • decidual stromal cells: 160 nCPM
  • cone photoreceptor cells: 108 nCPM

Immune cell

  • memory B-cell: 1.1 nTPM
  • classical monocyte: 0.9 nTPM
  • naive CD4 T-cell: 0.8 nTPM
  • total PBMC: 0.6 nTPM
  • naive CD8 T-cell: 0.5 nTPM
  • myeloid DC: 0.4 nTPM

Brain region

  • thalamus: 21 nTPM
  • basal ganglia: 21 nTPM
  • midbrain: 21 nTPM
  • medulla oblongata: 20 nTPM
  • pons: 18 nTPM
  • spinal cord: 17 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about SMTN.

Disease | ImmuneIEDB

Conditions an epitope on SMTN was assayed in.

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)
0.61
gnomAD pLI
0
gnomAD missense Z
0.79
DepMap mean gene effect
-0.14
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

Antibody and autoantibody relevanceSeroatlas analysis

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

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

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