ID   PSPB_RABIT              Reviewed;         370 AA.
AC   P15285; P79333;
DT   01-APR-1990, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1996, sequence version 2.
DT   27-MAR-2024, entry version 150.
DE   RecName: Full=Pulmonary surfactant-associated protein B;
DE            Short=SP-B;
DE   AltName: Full=6 kDa protein;
DE   AltName: Full=Pulmonary surfactant-associated proteolipid SPL(Phe);
DE   Flags: Precursor;
GN   Name=SFTPB; Synonyms=SFTP3;
OS   Oryctolagus cuniculus (Rabbit).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Euarchontoglires; Glires; Lagomorpha; Leporidae; Oryctolagus.
OX   NCBI_TaxID=9986;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Lung;
RX   PubMed=2469419; DOI=10.1016/0006-291x(89)91659-8;
RA   Xu J., Richardson C., Ford C., Spencer T., Li-Juan Y., Mackie G.,
RA   Hammond G., Possmayer F.;
RT   "Isolation and characterization of the cDNA for pulmonary surfactant-
RT   associated protein-B (SP-B) in the rabbit.";
RL   Biochem. Biophys. Res. Commun. 160:325-332(1989).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   STRAIN=New Zealand white;
RX   PubMed=7900830; DOI=10.1152/ajplung.1995.268.3.l481;
RA   Margana R.K., Boggaram V.;
RT   "Transcription and mRNA stability regulate developmental and hormonal
RT   expression of rabbit surfactant protein B gene.";
RL   Am. J. Physiol. 268:L481-L490(1995).
RN   [3]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   TISSUE=Liver;
RX   PubMed=8928820; DOI=10.1152/ajplung.1996.270.4.l601;
RA   Margana R.K., Boggaram V.;
RT   "Rabbit surfactant protein B gene: structure and functional
RT   characterization of the promoter.";
RL   Am. J. Physiol. 270:L601-L612(1996).
RN   [4]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 1-34.
RX   PubMed=8522191; DOI=10.1016/0378-1119(95)00506-2;
RA   Luzi P., Anceschi M., Strayer D.S.;
RT   "The upstream region of the SP-B gene: intrinsic promoter activity and
RT   glucocorticoid responsiveness related to a new DNA-binding protein.";
RL   Gene 165:285-290(1995).
CC   -!- FUNCTION: Pulmonary surfactant-associated proteins promote alveolar
CC       stability by lowering the surface tension at the air-liquid interface
CC       in the peripheral air spaces. SP-B increases the collapse pressure of
CC       palmitic acid to nearly 70 millinewtons per meter.
CC   -!- SUBUNIT: Homodimer; disulfide-linked.
CC   -!- SUBCELLULAR LOCATION: Secreted, extracellular space, surface film.
CC   -!- MISCELLANEOUS: Pulmonary surfactant consists of 90% lipid and 10%
CC       protein. There are 4 surfactant-associated proteins: 2 collagenous,
CC       carbohydrate-binding glycoproteins (SP-A and SP-D) and 2 small
CC       hydrophobic proteins (SP-B and SP-C).
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DR   EMBL; M24901; AAA31466.1; -; mRNA.
DR   EMBL; U17106; AAA67934.1; -; mRNA.
DR   EMBL; U40853; AAB48076.1; -; Genomic_DNA.
DR   EMBL; S80649; AAD14335.1; -; Genomic_DNA.
DR   PIR; A32421; LNRBB.
DR   PIR; I46531; I46531.
DR   RefSeq; NP_001075812.1; NM_001082343.1.
DR   RefSeq; XP_008250836.1; XM_008252614.2.
DR   RefSeq; XP_008250841.1; XM_008252619.2.
DR   RefSeq; XP_008250852.1; XM_008252630.2.
DR   AlphaFoldDB; P15285; -.
DR   SMR; P15285; -.
DR   BioGRID; 1172216; 1.
DR   STRING; 9986.ENSOCUP00000042591; -.
DR   GlyCosmos; P15285; 1 site, No reported glycans.
DR   PaxDb; 9986-ENSOCUP00000025658; -.
DR   Ensembl; ENSOCUT00000021287.1; ENSOCUP00000025658.1; ENSOCUG00000020733.4.
DR   GeneID; 100009194; -.
DR   KEGG; ocu:100009194; -.
DR   CTD; 6439; -.
DR   eggNOG; KOG1340; Eukaryota.
DR   GeneTree; ENSGT00940000161711; -.
DR   HOGENOM; CLU_063244_0_0_1; -.
DR   InParanoid; P15285; -.
DR   OMA; PKFWCQS; -.
DR   OrthoDB; 7299at2759; -.
DR   TreeFam; TF316942; -.
DR   Proteomes; UP000001811; Chromosome 2.
DR   Bgee; ENSOCUG00000020733; Expressed in upper lobe of left lung and 11 other cell types or tissues.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProt.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0006629; P:lipid metabolic process; IEA:InterPro.
DR   GO; GO:0007585; P:respiratory gaseous exchange by respiratory system; IEA:UniProtKB-KW.
DR   Gene3D; 1.10.225.10; Saposin-like; 2.
DR   InterPro; IPR003119; SAP_A.
DR   InterPro; IPR007856; SapB_1.
DR   InterPro; IPR008138; SapB_2.
DR   InterPro; IPR011001; Saposin-like.
DR   InterPro; IPR008139; SaposinB_dom.
DR   PANTHER; PTHR11480:SF33; PULMONARY SURFACTANT-ASSOCIATED PROTEIN B; 1.
DR   PANTHER; PTHR11480; SAPOSIN-RELATED; 1.
DR   Pfam; PF02199; SapA; 1.
DR   Pfam; PF05184; SapB_1; 1.
DR   Pfam; PF03489; SapB_2; 2.
DR   SMART; SM00162; SAPA; 1.
DR   SMART; SM00741; SapB; 3.
DR   SUPFAM; SSF47862; Saposin; 3.
DR   PROSITE; PS51110; SAP_A; 1.
DR   PROSITE; PS50015; SAP_B; 3.
PE   2: Evidence at transcript level;
KW   Disulfide bond; Gaseous exchange; Glycoprotein; Reference proteome; Repeat;
KW   Secreted; Signal; Surface film.
FT   SIGNAL          1..24
FT                   /evidence="ECO:0000255"
FT   PROPEP          25..184
FT                   /id="PRO_0000031653"
FT   CHAIN           185..263
FT                   /note="Pulmonary surfactant-associated protein B"
FT                   /id="PRO_0000031654"
FT   PROPEP          264..370
FT                   /id="PRO_0000031655"
FT   DOMAIN          26..66
FT                   /note="Saposin A-type"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00414"
FT   DOMAIN          66..148
FT                   /note="Saposin B-type 1"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DOMAIN          188..265
FT                   /note="Saposin B-type 2"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DOMAIN          284..359
FT                   /note="Saposin B-type 3"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   CARBOHYD        300
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        70..144
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        73..138
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        101..113
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        192..261
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        195..255
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        219..230
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        232
FT                   /note="Interchain"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        288..355
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        291..349
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   DISULFID        314..324
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00415"
FT   CONFLICT        15
FT                   /note="Missing (in Ref. 2; AAA67934)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        129
FT                   /note="Q -> L (in Ref. 3; AAB48076)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        184
FT                   /note="R -> P (in Ref. 1; AAA31466)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        232
FT                   /note="C -> R (in Ref. 2; AAA67934)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        289
FT                   /note="R -> P (in Ref. 3; AAB48076)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        329..355
FT                   /note="ELHTPQLLSLLSRGWDARAICQALGAC -> AAHAPAAEPAVQGLGCPRNLP
FT                   GPEGRV (in Ref. 1; AAA31466)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   370 AA;  40610 MW;  423047A69B12DCB5 CRC64;
     MAKSHLPPWL LLLLLPTLCG PGTAVWATSP LACAQGPEFW CQSLEQALQC KALGHCLQEV
     WGHVGADDLC QECQDIVNIL TKMTKEAIFQ DTIRKFLEHE CDVLPLKLLV PQCHHVLDVY
     FPLTITYFQS QINAKAICQH LGLCQPGSPE PPLDPLPDKL VLPTLLGALP AKPGPHTQDL
     SAQRFPIPLP LCWLCRTLLK RIQAMIPKGV LAMAVAQVCH VVPLVVGGIC QCLAERYTVI
     LLEVLLGHVL PQLVCGLVLR CSSVDSIGQV PPTLEALPGE WLPQDPECRL CMSVTTQARN
     ISEQTRPQAV YHACLSSQLD KQECEQFVEL HTPQLLSLLS RGWDARAICQ ALGACVATLS
     PLQCIQSPHF
//