P07988 (PSPB_HUMAN) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Pulmonary surfactant-associated protein B
Short name=SP-B

Alternative name(s):
18 kDa pulmonary-surfactant protein
6 kDa protein
Pulmonary surfactant-associated proteolipid SPL(Phe)

Gene names

Name:	SFTPB
Synonyms:	SFTP3

Organism

Homo sapiens (Human)

Taxonomic identifier

9606 [NCBI]

Taxonomic lineage

Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Mammalia › Eutheria › Euarchontoglires › Primates › Haplorrhini › Catarrhini › Hominidae › Homo

Protein attributes

Sequence length	381 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level

General annotation (Comments)

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.
Subunit structure	Homodimer; disulfide-linked. Ref.7
Subcellular location	Secreted › extracellular space › surface film.
Involvement in disease	Defects in SFTPB are the cause of pulmonary surfactant metabolism dysfunction type 1 (SMDP1) [MIM:265120]; also called pulmonary alveolar proteinosis due to surfactant protein B deficiency. A rare lung disorder due to impaired surfactant homeostasis. It is characterized by alveolar filling with floccular material that stains positive using the periodic acid-Schiff method and is derived from surfactant phospholipids and protein components. Excessive lipoproteins accumulation in the alveoli results in severe respiratory distress. Ref.9 Genetic variations in SFTPB are a cause of susceptibility to respiratory distress syndrome in premature infants (RDS) [MIM:267450]. RDS is a lung disease affecting usually premature newborn infants. It is characterized by deficient gas exchange, diffuse atelectasis, high-permeability lung edema and fibrin-rich alveolar deposits called 'hyaline membranes'. Note=A variation Ile to Thr at position 131 influences the association between specific alleles of SFTPA1 and respiratory distress syndrome in premature infants. Ref.11
Miscellaneous	Pulmonary surfactant consists of 90% lipid and 10% protein. There are 4 surfactant-associated proteins: 2 collagenous, carbohydrate-binding glycoproteins (SP-A and SP-D) and 2 small hydrophobic proteins (SP-B and SP-C).
Sequence similarities	Contains 1 saposin A-type domain. Contains 3 saposin B-type domains.
Sequence caution	The sequence AAA88099.1 differs from that shown. Reason: Erroneous initiation.

Ontologies

Keywords
Biological process	Gaseous exchange
Cellular component	Secreted Surface film
Coding sequence diversity	Polymorphism
Disease	Disease mutation
Domain	Repeat Signal
PTM	Disulfide bond Glycoprotein
Technical term	3D-structure Complete proteome Direct protein sequencing Reference proteome
Gene Ontology (GO)
Biological process	organ morphogenesis Traceable author statement. Source: ProtInc respiratory gaseous exchange Traceable author statement. Source: ProtInc sphingolipid metabolic process Inferred from electronic annotation. Source: InterPro
Cellular component	extracellular space Inferred from electronic annotation. Source: UniProtKB-SubCell lysosome Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Signal peptide

1 – 24

24

Potential

Propeptide

25 – 200

176

PRO_0000031647

Chain

201 – 279

79

Pulmonary surfactant-associated protein B

PRO_0000031648

Propeptide

280 – 381

102

PRO_0000031649

Regions

Domain

25 – 65

41

Saposin A-type

Domain

65 – 147

83

Saposin B-type 1

Domain

204 – 281

78

Saposin B-type 2

Domain

295 – 370

76

Saposin B-type 3

Amino acid modifications

Glycosylation

129

1

N-linked (GlcNAc...) Potential

Glycosylation

311

1

N-linked (GlcNAc...) Potential

Disulfide bond

69 ↔ 143

By similarity

Disulfide bond

72 ↔ 137

By similarity

Disulfide bond

100 ↔ 112

By similarity

Disulfide bond

208 ↔ 277

Ref.7

Disulfide bond

211 ↔ 271

Ref.7

Disulfide bond

235 ↔ 246

Ref.7

Disulfide bond

248

Interchain Ref.7

Disulfide bond

299 ↔ 366

By similarity

Disulfide bond

302 ↔ 360

By similarity

Disulfide bond

325 ↔ 335

By similarity

Natural variations

Natural variant

131

1

T → I. Ref.3 Ref.10
Corresponds to variant rs1130866 [ dbSNP | Ensembl ].

VAR_006948

Natural variant

176

1

L → F. Ref.3
Corresponds to variant rs3024801 [ dbSNP | Ensembl ].

VAR_013099

Natural variant

228

1

A → I Requires 2 nucleotide substitutions. Ref.7

VAR_006950

Natural variant

228

1

A → R Requires 2 nucleotide substitutions. Ref.2 Ref.5

VAR_006949

Natural variant

236

1

R → C in SMDP1. Ref.9

VAR_036856

Natural variant

272

1

R → H. Ref.3
Corresponds to variant rs3024809 [ dbSNP | Ensembl ].

VAR_013100

Experimental info

Sequence conflict

178

1

L → V in AAA36628. Ref.6

Sequence conflict

318

1

P → L in AAA88099. Ref.5

Secondary structure

1

.

.

.

.

.

.

381

Helix Strand Turn

Details...

Helix

208 – 221

14

Beta strand

265 – 268

4

Helix

269 – 276

8

Sequences

	Sequence		Length	Mass (Da)
	P07988 [UniParc]. Last modified May 1, 1992. Version 3. Checksum: 9FD7F66678A35153	FASTA	381	42,117
	10 20 30 40 50 60 MAESHLLQWL LLLLPTLCGP GTAAWTTSSL ACAQGPEFWC QSLEQALQCR ALGHCLQEVW 70 80 90 100 110 120 GHVGADDLCQ ECEDIVHILN KMAKEAIFQD TMRKFLEQEC NVLPLKLLMP QCNQVLDDYF 130 140 150 160 170 180 PLVIDYFQNQ TDSNGICMHL GLCKSRQPEP EQEPGMSDPL PKPLRDPLPD PLLDKLVLPV 190 200 210 220 230 240 LPGALQARPG PHTQDLSEQQ FPIPLPYCWL CRALIKRIQA MIPKGALAVA VAQVCRVVPL 250 260 270 280 290 300 VAGGICQCLA ERYSVILLDT LLGRMLPQLV CRLVLRCSMD DSAGPRSPTG EWLPRDSECH 310 320 330 340 350 360 LCMSVTTQAG NSSEQAIPQA MLQACVGSWL DREKCKQFVE QHTPQLLTLV PRGWDAHTTC 370 380 QALGVCGTMS SPLQCIHSPD L

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Isolation of a cDNA clone encoding a high molecular weight precursor to a 6-kDa pulmonary surfactant-associated protein." Jacobs K.A., Phelps D.S., Steinbrink R., Fisch J., Kriz R., Mitsock L., Dougherty J.P., Taeusch H.W., Floros J. J. Biol. Chem. 262:9808-9811(1987) [PubMed: 3597440] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 201-214. Tissue: Lung.
[2]	"Structure and organization of the gene encoding human pulmonary surfactant proteolipid SP-B." Pilot-Matias T.J., Kister S.E., Fox J.L., Kropp K., Glasser S.W., Whitsett J.A. DNA 8:75-86(1989) [PubMed: 2924687] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], VARIANT ARG-228.
[3]	SeattleSNPs variation discovery resource Submitted (JUL-2001) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], VARIANTS ILE-131; PHE-176 AND HIS-272.
[4]	"The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)." The MGC Project Team Genome Res. 14:2121-2127(2004) [PubMed: 15489334] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA]. Tissue: Brain.
[5]	"cDNA and deduced amino acid sequence of human pulmonary surfactant-associated proteolipid SPL(Phe)." Glasser S.W., Korfhagen T.R., Weaver T., Pilot-Matias T., Fox J.L., Whitsett J.A. Proc. Natl. Acad. Sci. U.S.A. 84:4007-4011(1987) [PubMed: 3035561] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA] OF 99-381, VARIANT ARG-228.
[6]	"Use of human surfactant low molecular weight apoproteins in the reconstitution of surfactant biologic activity." Revak S.D., Merritt T.A., Degryse E., Stefani L., Courtney M., Hallman M., Cochrane C.G. J. Clin. Invest. 81:826-833(1988) [PubMed: 3343343] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA] OF 139-381.
[7]	"Human surfactant polypeptide SP-B. Disulfide bridges, C-terminal end, and peptide analysis of the airway form." Johansson J., Joernvall H., Curstedt T. FEBS Lett. 301:165-167(1992) [PubMed: 1568474] [Abstract] Cited for: PROTEIN SEQUENCE OF 201-279, DISULFIDE BONDS, VARIANT ILE-228.
[8]	"Conformational mapping of the N-terminal segment of surfactant protein B in lipid using 13C-enhanced Fourier transform infrared spectroscopy." Gordon L.M., Lee K.Y., Lipp M.M., Zasadzinski J.A., Walther F.J., Sherman M.A., Waring A.J. J. Pept. Res. 55:330-347(2000) [PubMed: 10798379] [Abstract] Cited for: STRUCTURE BY FTIR OF 201-225.
[9]	"Partial deficiency of surfactant protein B in an infant with chronic lung disease." Ballard P.L., Nogee L.M., Beers M.F., Ballard R.A., Planer B.C., Polk L., deMello D.E., Moxley M.A., Longmore W.J. Pediatrics 96:1046-1052(1995) [PubMed: 7491219] [Abstract] Cited for: VARIANT SMDP1 CYS-236.
[10]	"Polymorphisms of human SP-A, SP-B, and SP-D genes: association of SP-B Thr131Ile with ARDS." Lin Z., Pearson C., Chinchilli V., Pietschmann S.M., Luo J., Pison U., Floros J. Clin. Genet. 58:181-191(2000) [PubMed: 11076040] [Abstract] Cited for: VARIANT ILE-131.
[11]	"Surfactant proteins A and B as interactive genetic determinants of neonatal respiratory distress syndrome." Haataja R., Raemet M., Marttila R., Hallman M. Hum. Mol. Genet. 9:2751-2760(2000) [PubMed: 11063734] [Abstract] Cited for: INVOLVEMENT IN SUSCEPTIBILITY TO RDS.
+	Additional computationally mapped references.

Web resources

GeneReviews

SeattleSNPs

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

J02761 mRNA. Translation: AAA60212.1.
M24461 Genomic DNA. Translation: AAB59541.1.
AF400074 Genomic DNA. Translation: AAK77913.1.
BC032785 mRNA. Translation: AAH32785.1.
M16764 mRNA. Translation: AAA88099.1. Different initiation.
M19097 mRNA. Translation: AAA36628.1.

IPI

IPI00296083.

PIR

LNHUB. A31361.

RefSeq

NP_000533.3. NM_000542.3.
NP_942140.2. NM_198843.2.

UniGene

Hs.512690.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1DFW	infrared	-	A	201-225	[»]
1KMR	NMR	-	A	211-225	[»]
1RG3	NMR	-	A	263-278	[»]
1RG4	NMR	-	A	263-278	[»]
1SSZ	infrared	-	A	208-278	[»]
2DWF	NMR	-	A	208-278	[»]
2JOU	NMR	-	A	208-278	[»]

ProteinModelPortal

P07988.

SMR

P07988. Positions 68-145, 206-281, 296-368.

ModBase

Search...

Protein-protein interaction databases

STRING

P07988.

Polymorphism databases

DMDM

131418.

Proteomic databases

PRIDE

P07988.

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Genome annotation databases

Ensembl

ENST00000342375; ENSP00000345161; ENSG00000168878.
ENST00000393822; ENSP00000377409; ENSG00000168878.
ENST00000409383; ENSP00000386346; ENSG00000168878.

GeneID

6439.

KEGG

hsa:6439.

UCSC

uc002sqh.1. human.

Organism-specific databases

CTD

6439.

GeneCards

GC02M085884.

H-InvDB

HIX0002227.

HGNC

HGNC:10801. SFTPB.

HPA

CAB002440.

MIM

178640. gene.
265120. phenotype.
267450. phenotype.

neXtProt

NX_P07988.

Orphanet

264675. Congenital pulmonary alveolar proteinosis.
70587. Infant acute respiratory distress syndrome.
217563. Neonatal acute respiratory distress with surfactant metabolism deficiency.

PharmGKB

PA35713.

GenAtlas

Search...

Phylogenomic databases

GeneTree

ENSGT00530000063434.

HOGENOM

HBG283252.

HOVERGEN

HBG006905.

InParanoid

P07988.

OMA

VWGHVGA.

OrthoDB

EOG434W6C.

PhylomeDB

P07988.

Gene expression databases

ArrayExpress

P07988.

Bgee

P07988.

CleanEx

HS_SFTPB.

Genevestigator

P07988.

GermOnline

ENSG00000168878. Homo sapiens.

Family and domain databases

InterPro

IPR003119. SapA.
IPR007856. SapB_1.
IPR008138. SapB_2.
IPR008373. Saposin.
IPR011001. Saposin-like.
IPR008139. SaposinB.
[Graphical view]

Gene3D

G3DSA:1.10.225.10. Saposin_like. 3 hits.

Pfam

PF02199. SapA. 1 hit.
PF05184. SapB_1. 1 hit.
PF03489. SapB_2. 3 hits.
[Graphical view]

PRINTS

PR01797. SAPOSIN.

SMART

SM00162. SAPA. 1 hit.
SM00741. SapB. 3 hits.
[Graphical view]

SUPFAM

SSF47862. Saposin_like. 3 hits.

PROSITE

PS51110. SAP_A. 1 hit.
PS50015. SAP_B. 3 hits.
[Graphical view]

ProtoNet

Search...

Other

NextBio

25021.

PMAP-CutDB

P07988.

SOURCE

Search...

Entry information

Entry name

PSPB_HUMAN

Accession

Primary (citable) accession number: P07988
Secondary accession number(s): Q96R04

Entry history

Integrated into UniProtKB/Swiss-Prot:	August 1, 1988
Last sequence update:	May 1, 1992
Last modified:	January 25, 2012
This is version 146 of the entry and version 3 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Chordata Protein Annotation Program

Disclaimer

Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care.