Seroatlas · Human Serome Atlas

SFTPB

Pulmonary surfactant-associated protein B

Also known as: PSPB_HUMAN, SFTP3, SP-B

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

Protein identityUniProt · HPA

UniProt accession
P07988
Gene
SFTPB
Ensembl
ENSG00000168878
Chromosome
2
Canonical length
381 aa
Protein class
Disease related genes, Human disease related genes, Plasma proteins, Predicted intracellular proteins, Predicted secreted proteins
Secretome location
Secreted in other tissues
Quaternary structure
Homodimer

OverviewNCBI Gene

This gene encodes the pulmonary-associated surfactant protein B (SPB), an amphipathic surfactant protein essential for lung function and homeostasis after birth. Pulmonary surfactant is a surface-active lipoprotein complex composed of 90% lipids and 10% proteins which include plasma proteins and apolipoproteins SPA, SPB, SPC and SPD. The surfactant is secreted by the alveolar cells of the lung and maintains the stability of pulmonary tissue by reducing the surface tension of fluids that coat the lung. The SPB enhances the rate of spreading and increases the stability of surfactant monolayers in vitro. Multiple mutations in this gene have been identified, which cause pulmonary surfactant metabolism dysfunction type 1, also called pulmonary alveolar proteinosis due to surfactant protein B deficiency, and are associated with fatal respiratory distress in the neonatal period. Alternatively spliced transcript variants encoding the same protein have been identified.[provided by RefSeq, Feb 2010]

Canonical amino-acid sequenceUniProt

381 residues, UniProt reviewed canonical sequence.

>P07988|SFTPB
     1  MAESHLLQWL LLLLPTLCGP GTAAWTTSSL ACAQGPEFWC QSLEQALQCR ALGHCLQEVW
    61  GHVGADDLCQ ECEDIVHILN KMAKEAIFQD TMRKFLEQEC NVLPLKLLMP QCNQVLDDYF
   121  PLVIDYFQNQ TDSNGICMHL GLCKSRQPEP EQEPGMSDPL PKPLRDPLPD PLLDKLVLPV
   181  LPGALQARPG PHTQDLSEQQ FPIPLPYCWL CRALIKRIQA MIPKGALAVA VAQVCRVVPL
   241  VAGGICQCLA ERYSVILLDT LLGRMLPQLV CRLVLRCSMD DSAGPRSPTG EWLPRDSECH
   301  LCMSVTTQAG NSSEQAIPQA MLQACVGSWL DREKCKQFVE QHTPQLLTLV PRGWDAHTTC
   361  QALGVCGTMS SPLQCIHSPD L

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SFTPB 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
Secreted
Secreted
Yes
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.45
Highest tissue expression
3,361 nTPM

Expression across tissuesHPA

Tissue

  • lung: 3,361 nTPM
  • thyroid gland: 111 nTPM
  • ovary: 9.7 nTPM
  • pituitary gland: 5.1 nTPM
  • stomach: 4.8 nTPM
  • adrenal gland: 4.1 nTPM

Single-cell type

  • alveolar cells type 2: 19,161 nCPM
  • transitional alveolar cells: 14,488 nCPM
  • alveolar cells type 1: 9,996 nCPM
  • respiratory deuterosomal cells: 654 nCPM
  • respiratory ionocytes: 163 nCPM
  • respiratory ciliated cells: 121 nCPM

Immune cell

  • intermediate monocyte: 1.1 nTPM
  • non-classical monocyte: 0.7 nTPM
  • classical monocyte: 0.6 nTPM
  • neutrophil: 0.6 nTPM
  • myeloid DC: 0.4 nTPM
  • T-reg: 0.4 nTPM

Brain region

  • cerebral cortex: 5.5 nTPM
  • hypothalamus: 5.3 nTPM
  • cerebellum: 4.3 nTPM
  • pons: 4.1 nTPM
  • amygdala: 4 nTPM
  • thalamus: 3.9 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about SFTPB.

Disease | AllUniProt

Conditions SFTPB is implicated in, by any mechanism.

  • Pulmonary surfactant metabolism dysfunction 1 (SMDP1) MIM:265120
  • Respiratory distress syndrome in premature infants (RDS) MIM:267450

Disease | GeneticClinVar

19 pathogenic / likely-pathogenic of 254 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

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)
0.72
gnomAD pLI
0
gnomAD missense Z
0.6
DepMap mean gene effect
-0.23
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 2% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

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

SFTPB is annotated as secreted, so native SFTPB circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

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

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