SFTPB (surfactant protein B)

Gene

• Entrez ID: 6439
• Gene name: Surfactant protein B
• Gene symbol: SFTPB
• Synonyms: PSP-B, SFTB3, SFTP3, SMDP1, SP-B
• Chromosome: 2
• Chromosome location: 2p11.2
• Summary: 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]

SNPs

SNP ID	Visualize variation	Clinical significance	Consequence
rs35328240	G>TTC	Pathogenic	Coding sequence variant, frameshift variant
rs35373464	C>T	Conflicting-interpretations-of-pathogenicity	Coding sequence variant, missense variant
rs137853202	G>A	Pathogenic	Coding sequence variant, missense variant
rs779795223	->TT	Pathogenic	Frameshift variant, coding sequence variant
rs1553380888	C>A	Pathogenic	Coding sequence variant, synonymous variant
rs1558572491	C>T	Pathogenic	Intron variant, genic downstream transcript variant, splice acceptor variant

miRNA

miRTarBase ID	miRNA	Experiments	Reference
MIRT508420	hsa-miR-3187-3p	PAR-CLIP	23446348
MIRT508421	hsa-miR-6807-5p	PAR-CLIP	23446348
MIRT508422	hsa-miR-4529-5p	PAR-CLIP	23446348
MIRT508423	hsa-miR-3176	PAR-CLIP	23446348
MIRT508424	hsa-miR-3922-3p	PAR-CLIP	23446348
MIRT508425	hsa-miR-3190-5p	PAR-CLIP	23446348
MIRT508426	hsa-miR-3934-5p	PAR-CLIP	23446348
MIRT508427	hsa-miR-6807-3p	PAR-CLIP	23446348
MIRT508428	hsa-miR-217	PAR-CLIP	23446348
MIRT508429	hsa-miR-509-5p	PAR-CLIP	23446348
MIRT508430	hsa-miR-509-3-5p	PAR-CLIP	23446348
MIRT508431	hsa-miR-4418	PAR-CLIP	23446348
MIRT512439	hsa-miR-514b-5p	PAR-CLIP	23446348
MIRT512440	hsa-miR-513c-5p	PAR-CLIP	23446348
MIRT512441	hsa-miR-524-5p	PAR-CLIP	23446348
MIRT512442	hsa-miR-520d-5p	PAR-CLIP	23446348
MIRT512443	hsa-miR-330-3p	PAR-CLIP	23446348
MIRT512444	hsa-miR-6504-3p	PAR-CLIP	23446348
MIRT512445	hsa-miR-6835-3p	PAR-CLIP	23446348
MIRT514813	hsa-miR-6811-5p	PAR-CLIP	23446348
MIRT514814	hsa-miR-6511b-5p	PAR-CLIP	23446348
MIRT514815	hsa-miR-657	PAR-CLIP	23446348
MIRT514816	hsa-miR-3665	PAR-CLIP	23446348
MIRT716058	hsa-miR-133a-3p	HITS-CLIP	19536157
MIRT716059	hsa-miR-5587-5p	HITS-CLIP	19536157
MIRT716060	hsa-miR-4281	HITS-CLIP	19536157
MIRT716061	hsa-miR-7153-3p	HITS-CLIP	19536157

Transcription factors

Transcription factor	Regulation	Reference
FOXA1	Activation	18003659
FOXM1	Activation	12161428
MYBBP1A	Unknown	11274148
NF1	Unknown	7580940
NKX2-1	Activation	12161428;18003659;8065304
NKX2-1	Unknown	11274148
RARA	Unknown	10070102

Gene ontology (GO)

GO ID	Ontology	Definition	Evidence	Reference
GO:0005515	Function	Protein binding	IPI	32296183
GO:0005576	Component	Extracellular region	TAS
GO:0005615	Component	Extracellular space	IBA	21873635
GO:0005654	Component	Nucleoplasm	TAS
GO:0005764	Component	Lysosome	IEA
GO:0005771	Component	Multivesicular body	IBA	21873635
GO:0005789	Component	Endoplasmic reticulum membrane	TAS
GO:0006665	Process	Sphingolipid metabolic process	IEA
GO:0007585	Process	Respiratory gaseous exchange by respiratory system	IEA
GO:0009887	Process	Animal organ morphogenesis	TAS	10378403
GO:0042599	Component	Lamellar body	TAS
GO:0044267	Process	Cellular protein metabolic process	TAS
GO:0045334	Component	Clathrin-coated endocytic vesicle	TAS
GO:0097208	Component	Alveolar lamellar body	IBA	21873635
GO:0097486	Component	Multivesicular body lumen	TAS

Other IDs

• MIM: 178640
• HGNC: 10801
• e!Ensembl: ENSG00000168878

Protein

• UniProt ID: P07988
• Protein name: Pulmonary surfactant-associated protein B (SP-B) (18 kDa pulmonary-surfactant protein) (6 kDa protein) (Pulmonary surfactant-associated proteolipid SPL(Phe))
• Protein function: Pulmonary surfactant-associated proteins promote alveolar stability by lowering the surface tension at the air-liquid interface in the peripheral air spaces. SP-B increases the collapse pressure of palmitic acid to nearly 70 millinewtons per meter.
• PDB: 1DFW, 1KMR, 1RG3, 1RG4, 1SSZ, 2DWF, 2JOU, 2M0H, 2M1T
• Family and domains:

  Pfam

  Accession	ID	Position in sequence	Description	Type
  PF02199	SapA	30 → 61	Saposin A-type domain	Family
  PF05184	SapB_1	67 → 104	Saposin-like type B, region 1	Domain
  PF03489	SapB_2	110 → 143	Saposin-like type B, region 2	Family
  PF03489	SapB_2	333 → 366	Saposin-like type B, region 2	Family

• Sequence:

  MAESHLLQWLLLLLPTLCGPGTAAWTTSSLACAQGPEFWCQSLEQALQCRALGHCLQEVW
  GHVGADDLCQECEDIVHILNKMAKEAIFQDTMRKFLEQECNVLPLKLLMPQCNQVLDDYF
  PLVIDYFQNQTDSNGICMHLGLCKSRQPEPEQEPGMSDPLPKPLRDPLPDPLLDKLVLPV
  LPGALQARPGPHTQDLSEQQFPIPLPYCWLCRALIKRIQAMIPKGALAVAVAQVCRVVPL
  VAGGICQCLAERYSVILLDTLLGRMLPQLVCRLVLRCSMDDSAGPRSPTGEWLPRDSECH
  LCMSVTTQAGNSSEQAIPQAMLQACVGSWLDREKCKQFVEQHTPQLLTLVPRGWDAHTTC
  QALGVCGTMSSPLQCIHSPDL

• Sequence length: 381

Pathways

Reactome:

Surfactant metabolism
Defective pro-SFTPB causes pulmonary surfactant metabolism dysfunction 1 (SMDP1) and respiratory distress syndrome (RDS)
Defective CSF2RB causes pulmonary surfactant metabolism dysfunction 5 (SMDP5)
Defective CSF2RA causes pulmonary surfactant metabolism dysfunction 4 (SMDP4)

Associated diseases

Disease name	Disease term	References
	Pulmonary Alveolar Proteinosis
	Respiratory Distress Syndrome, Newborn	11063734
	Hyaline Membrane Disease	11063734
	Lung Neoplasms	16570259
	Malignant neoplasm of lung	16570259
	Lung diseases	16863852
	Lung Diseases, Interstitial
	Chronic lung disease
	Pulmonary arterial hypertension
	Idiopathic pulmonary arterial hypertension
	Neonatal acute respiratory distress due to SP-B deficiency
	Respiratory Distress Syndrome	11063734
	Infant acute respiratory distress syndrome
	Respiratory Failure
	Surfactant Metabolism Dysfunction, Pulmonary, 1	7491219, 23330012, 26199800, 23625987, 21965505, 10712351, 15331184, 8163685
	Right Ventricular Hypertrophy