P50405 (PSPB_MOUSE) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

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

Alternative name(s):
Pulmonary surfactant-associated proteolipid SPL(Phe)

Gene names

Name:	Sftpb
Synonyms:	Sftp3

Organism

Mus musculus (Mouse) [Reference proteome]

Taxonomic identifier

10090 [NCBI]

Taxonomic lineage

cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Deuterostomia › Chordata › Craniata › Vertebrata › Gnathostomata › Teleostomi › Euteleostomi › Sarcopterygii › Tetrapoda › Amniota › Mammalia › Theria › Eutheria › Euarchontoglires › Glires › Rodentia › Sciurognathi › Muroidea › Muridae › Murinae › Mus › Mus

Protein attributes

Sequence length	377 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at transcript 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.
Subcellular location	Secreted › extracellular space › surface film.
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.

Ontologies

Keywords
Biological process	Gaseous exchange
Cellular component	Secreted Surface film
Domain	Repeat Signal
PTM	Disulfide bond Glycoprotein
Technical term	Complete proteome Reference proteome
Gene Ontology (GO)
Biological_process	respiratory gaseous exchange Inferred from electronic annotation. Source: UniProtKB-KW sphingolipid metabolic process Inferred from electronic annotation. Source: InterPro
Cellular_component	cytoplasm Inferred from direct assay PubMed 8813084. Source: MGI 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 – 22	22	Potential
	Propeptide	23 – 191	169			PRO_0000031650
	Chain	192 – 270	79	Pulmonary surfactant-associated protein B		PRO_0000031651
	Propeptide	271 – 377	107			PRO_0000031652
Regions
	Domain	24 – 64	41	Saposin A-type
	Domain	64 – 146	83	Saposin B-type 1
	Domain	195 – 272	78	Saposin B-type 2
	Domain	291 – 366	76	Saposin B-type 3
Amino acid modifications
	Glycosylation	307	1	N-linked (GlcNAc...) Potential
	Disulfide bond	68 ↔ 142		By similarity
	Disulfide bond	71 ↔ 136		By similarity
	Disulfide bond	99 ↔ 111		By similarity
	Disulfide bond	199 ↔ 268		By similarity
	Disulfide bond	202 ↔ 262		By similarity
	Disulfide bond	226 ↔ 237		By similarity
	Disulfide bond	239		Interchain By similarity
	Disulfide bond	295 ↔ 362		By similarity
	Disulfide bond	298 ↔ 356		By similarity
	Disulfide bond	321 ↔ 331		By similarity

Sequences

	Sequence		Length	Mass (Da)
	P50405 [UniParc]. Last modified October 1, 1996. Version 1. Checksum: CB687A82BA3FC56C	FASTA	377	41,728
	10 20 30 40 50 60 MAKSHLLQWL LLLPTLCCPG AAITSASSLE CAQGPQFWCQ SLEHAVQCRA LGHCLQEVWG 70 80 90 100 110 120 HAGANDLCQE CEDIVHLLTK MTKEDAFQEA IRKFLEQECD ILPLKLLVPR CRQVLDVYLP 130 140 150 160 170 180 LVIDYFQSQI NPKAICNHVG LCPRGQAKPE QNPGMPDAVP NPLLDKLVLP VLPGALLARP 190 200 210 220 230 240 GPHTQDFSEQ QLPIPLPFCW LCRTLIKRVQ AVIPKGVLAV AVSQVCHVVP LVVGGICQCL 250 260 270 280 290 300 AERYTVLLLD ALLGRVVPQL VCGLVLRCST EDAMGPALPA VEPLIEEWPL QDTECHFCKS 310 320 330 340 350 360 VINQAWNTSE QAMPQAMHQA CLRFWLDRQK CEQFVEQHMP QLLALVPRSQ DAHITCQALG 370 VCEAPASPLQ CFQTPHL

References

[1]	"Structure and function of the mouse surfactant protein B gene." Bruno M.A., Bohinski R.J., Carter J.E., Foss K.A., Whitsett J.A. Am. J. Physiol. 268:L381-L389(1995) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]. Strain: DBA/2J. Tissue: Liver.
+	Additional computationally mapped references.

Cross-references

Sequence databases
EMBL GenBank DDBJ	S78114 Genomic DNA. Translation: AAB34846.2.
IPI	IPI00117977.
RefSeq	NP_680088.1. NM_147779.1.
UniGene	Mm.46033.
3D structure databases
ProteinModelPortal	P50405.
SMR	P50405. Positions 68-142.
ModBase	Search...
Protein-protein interaction databases
STRING	10090.ENSMUSP00000066805.
Proteomic databases
PaxDb	P50405.
PRIDE	P50405.
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Genome annotation databases
GeneID	20388.
KEGG	mmu:20388.
UCSC	uc009cid.1. mouse.
Organism-specific databases
CTD	6439.
MGI	MGI:109516. Sftpb.
Phylogenomic databases
eggNOG	NOG286450.
HOGENOM	HOG000115745.
HOVERGEN	HBG006905.
InParanoid	P50405.
OrthoDB	EOG434W6C.
Gene expression databases
ArrayExpress	P50405.
Bgee	P50405.
CleanEx	MM_SFTPB.
Genevestigator	P50405.
GermOnline	ENSMUSG00000056370. Mus musculus.
Family and domain databases
Gene3D	1.10.225.10. 3 hits.
InterPro	IPR003119. SapA. IPR007856. SapB_1. IPR008138. SapB_2. IPR008373. Saposin. IPR011001. Saposin-like. IPR008139. SaposinB. [Graphical view]
Pfam	PF02199. SapA. 1 hit. PF05184. SapB_1. 1 hit. PF03489. SapB_2. 2 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	298318.
SOURCE	Search...

Entry information

Entry name

PSPB_MOUSE

Accession

Primary (citable) accession number: P50405

Entry history

Integrated into UniProtKB/Swiss-Prot:	October 1, 1996
Last sequence update:	October 1, 1996
Last modified:	May 1, 2013
This is version 98 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Chordata Protein Annotation Program