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Protein

Prosaposin

Gene

PSAP

Organism
Bos taurus (Bovine)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Saposin-A and saposin-C stimulate the hydrolysis of glucosylceramide by beta-glucosylceramidase (EC 3.2.1.45) and galactosylceramide by beta-galactosylceramidase (EC 3.2.1.46). Saposin-C apparently acts by combining with the enzyme and acidic lipid to form an activated complex, rather than by solubilizing the substrate.By similarity
Saposin-B stimulates the hydrolysis of galacto-cerebroside sulfate by arylsulfatase A (EC 3.1.6.8), GM1 gangliosides by beta-galactosidase (EC 3.2.1.23) and globotriaosylceramide by alpha-galactosidase A (EC 3.2.1.22). Saposin-B forms a solubilizing complex with the substrates of the sphingolipid hydrolases.By similarity
Saposin-D is a specific sphingomyelin phosphodiesterase activator (EC 3.1.4.12).By similarity
Prosaposin: Behaves as a myelinotrophic and neurotrophic factor, these effects are mediated by its G-protein-coupled receptors, GPR37 and GPR37L1, undergoing ligand-mediated internalization followed by ERK phosphorylation signaling.By similarity
Saposins are specific low-molecular mass non-enzymic proteins, they participate in the lysosomal degradation of sphingolipids, which takes place by the sequential action of specific hydrolases.By similarity

GO - Molecular functioni

GO - Biological processi

Complete GO annotation...

Keywords - Biological processi

Lipid metabolism, Sphingolipid metabolism

Names & Taxonomyi

Protein namesi
Recommended name:
Prosaposin
Alternative name(s):
Proactivator polypeptide
Cleaved into the following 4 chains:
Alternative name(s):
Protein A
Alternative name(s):
Cerebroside sulfate activator
Short name:
CSAct
Dispersin
Sphingolipid activator protein 1
Short name:
SAP-1
Sulfatide/GM1 activator
Alternative name(s):
A1 activator
Co-beta-glucosidase
Glucosylceramidase activator
Sphingolipid activator protein 2
Short name:
SAP-2
Alternative name(s):
Component C
Protein C
Gene namesi
Name:PSAP
OrganismiBos taurus (Bovine)
Taxonomic identifieri9913 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaLaurasiatheriaCetartiodactylaRuminantiaPecoraBovidaeBovinaeBos
Proteomesi
  • UP000009136 Componenti: Unplaced

Subcellular locationi

Prosaposin :
  • Secreted

  • Note: Secreted as a fully glycosylated 70 kDa protein composed of complex glycans.By similarity

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Lysosome, Secreted

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Signal peptidei1 – 1616By similarityAdd
BLAST
Chaini17 – 525509ProsaposinBy similarityPRO_0000424773Add
BLAST
Propeptidei17 – 5943By similarityPRO_0000031607Add
BLAST
Chaini60 – 14283Saposin-ABy similarityPRO_0000031608Add
BLAST
Propeptidei143 – 19553By similarityPRO_0000031609Add
BLAST
Chaini196 – 27580Saposin-BBy similarityPRO_0000031610Add
BLAST
Propeptidei276 – 311361 PublicationPRO_0000031611Add
BLAST
Chaini312 – 39180Saposin-C1 PublicationPRO_0000031612Add
BLAST
Propeptidei392 – 405141 PublicationPRO_0000031613Add
BLAST
Chaini406 – 48782Saposin-DBy similarityPRO_0000031614Add
BLAST
Propeptidei488 – 52538By similarityPRO_0000031615Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Disulfide bondi63 ↔ 138PROSITE-ProRule annotation
Disulfide bondi66 ↔ 132PROSITE-ProRule annotation
Glycosylationi80 – 801N-linked (GlcNAc...)PROSITE-ProRule annotation
Disulfide bondi94 ↔ 106PROSITE-ProRule annotation
Glycosylationi101 – 1011N-linked (GlcNAc...)PROSITE-ProRule annotation
Disulfide bondi199 ↔ 272PROSITE-ProRule annotation
Disulfide bondi202 ↔ 266PROSITE-ProRule annotation
Glycosylationi216 – 2161N-linked (GlcNAc...)PROSITE-ProRule annotation
Disulfide bondi231 ↔ 242PROSITE-ProRule annotation
Disulfide bondi316 ↔ 389PROSITE-ProRule annotation
Disulfide bondi319 ↔ 383PROSITE-ProRule annotation
Glycosylationi333 – 3331N-linked (GlcNAc...)
Disulfide bondi347 ↔ 358PROSITE-ProRule annotation
Disulfide bondi410 ↔ 483PROSITE-ProRule annotation
Disulfide bondi413 ↔ 477PROSITE-ProRule annotation
Glycosylationi427 – 4271N-linked (GlcNAc...)PROSITE-ProRule annotation
Disulfide bondi441 ↔ 452PROSITE-ProRule annotation

Post-translational modificationi

The lysosomal precursor is proteolytically processed to 4 small peptides, which are similar to each other and are sphingolipid hydrolase activator proteins.By similarity

Keywords - PTMi

Cleavage on pair of basic residues, Disulfide bond, Glycoprotein

Proteomic databases

PaxDbiP26779.
PeptideAtlasiP26779.
PRIDEiP26779.

Interactioni

Subunit structurei

Saposin-B is a homodimer. Prosaposin exists as a roughly half-half mixture of monomers and disulfide-linked dimers. Monomeric prosaposin interacts (via C-terminus) with sortilin/SORT1, the interaction is required for targeting to lysosomes (By similarity).By similarity

GO - Molecular functioni

Protein-protein interaction databases

STRINGi9913.ENSBTAP00000044260.

Structurei

3D structure databases

ProteinModelPortaliP26779.
SMRiP26779. Positions 60-140, 195-273, 312-390, 406-485.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Domaini18 – 5841Saposin A-type 1PROSITE-ProRule annotationAdd
BLAST
Domaini59 – 14284Saposin B-type 1PROSITE-ProRule annotationAdd
BLAST
Domaini195 – 27682Saposin B-type 2PROSITE-ProRule annotationAdd
BLAST
Domaini312 – 39382Saposin B-type 3PROSITE-ProRule annotationAdd
BLAST
Domaini406 – 48782Saposin B-type 4PROSITE-ProRule annotationAdd
BLAST
Domaini489 – 52537Saposin A-type 2PROSITE-ProRule annotationAdd
BLAST

Sequence similaritiesi

Contains 2 saposin A-type domains.PROSITE-ProRule annotation
Contains 4 saposin B-type domains.PROSITE-ProRule annotation

Keywords - Domaini

Repeat, Signal

Phylogenomic databases

eggNOGiKOG1340. Eukaryota.
ENOG410XSI5. LUCA.
HOGENOMiHOG000049216.
HOVERGENiHBG002617.
InParanoidiP26779.
KOiK12382.
OrthoDBiEOG7ZSHSC.
TreeFamiTF316942.

Family and domain databases

Gene3Di1.10.225.10. 4 hits.
InterProiIPR003119. SAP_A.
IPR007856. SapB_1.
IPR008138. SapB_2.
IPR008373. Saposin.
IPR011001. Saposin-like.
IPR021165. Saposin_chordata.
IPR008139. SaposinB_dom.
[Graphical view]
PfamiPF02199. SapA. 2 hits.
PF05184. SapB_1. 4 hits.
PF03489. SapB_2. 4 hits.
[Graphical view]
PIRSFiPIRSF002431. Saposin. 1 hit.
PRINTSiPR01797. SAPOSIN.
SMARTiSM00162. SAPA. 2 hits.
SM00741. SapB. 4 hits.
[Graphical view]
SUPFAMiSSF47862. SSF47862. 4 hits.
PROSITEiPS51110. SAP_A. 2 hits.
PS50015. SAP_B. 4 hits.
[Graphical view]

Sequences (2)i

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

This entry describes 2 isoformsi produced by alternative splicing. AlignAdd to basket

Isoform 1 (identifier: P26779-1) [UniParc]FASTAAdd to basket

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

« Hide

        10         20         30         40         50
MYSFFVLASL LGGALASPVL GLRECTRGSA VWCQNVKTAA DCGAVQHCLQ
60 70 80 90 100
TVWSKPTVKS LPCDICKDVI TAAGNLLKDN ATEQEILMYL ERTCDWLPKP
110 120 130 140 150
NMSASCKEIV DSYLPVILDM IKGQMSHPGE VCSALNLCES LQKHLAELNH
160 170 180 190 200
QKQLESNQIP ELDMAEVVAP FMANIPFLLY PQDGSHSKPQ PKKANGNVCQ
210 220 230 240 250
DCIQLVTDVQ EALRTNSTFV EALVDHAKEE CDRLGPGMSD MCKNYINQYS
260 270 280 290 300
EVAIQMVMHM QPKEICVLAG FCDEVKEMPM KTLVPAEVVS ENVIPALGLV
310 320 330 340 350
EPIKKDPAPA KADIYCEVCE FVVKEVAKLI DNNRTEEEIL HALDKVCSKL
360 370 380 390 400
PTSLAEQCQE VVDTYGSSIL SILLDEASPE LVCSMLHLCS SRGLPAATVR
410 420 430 440 450
VMPRKDGGFC EVCKKLVGYL DRNLEKNSTK EQILAALEKG CSFLPDQYRK
460 470 480 490 500
QCDQFVTEYE PVLIEILVEV MDPSFVCLKI GACPAAHKPL LGAEKCVWGP
510 520
SYWCQNMESA ALCNAVEHCR RHVWN
Length:525
Mass (Da):58,051
Last modified:October 3, 2006 - v3
Checksum:i2734E6BFB86FE092
GO
Isoform 2 (identifier: P26779-2) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     261-261: Q → QDQQ

Show »
Length:528
Mass (Da):58,423
Checksum:i7EC0EEAC6082975A
GO

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti71 – 711T → I in AAI05410 (Ref. 2) Curated
Sequence conflicti317 – 3171E → Q AA sequence (PubMed:1554743).Curated
Sequence conflicti367 – 3671S → R AA sequence (PubMed:1554743).Curated

Natural variant

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Natural varianti127 – 1271H → R.1 Publication

Alternative sequence

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Alternative sequencei261 – 2611Q → QDQQ in isoform 2. 2 PublicationsVSP_020782

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AB036791 mRNA. Translation: BAA95677.1.
BC105409 mRNA. Translation: AAI05410.1.
RefSeqiNP_776586.1. NM_174161.3. [P26779-1]
UniGeneiBt.42764.

Genome annotation databases

GeneIDi281433.
KEGGibta:281433.

Keywords - Coding sequence diversityi

Alternative splicing, Polymorphism

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AB036791 mRNA. Translation: BAA95677.1.
BC105409 mRNA. Translation: AAI05410.1.
RefSeqiNP_776586.1. NM_174161.3. [P26779-1]
UniGeneiBt.42764.

3D structure databases

ProteinModelPortaliP26779.
SMRiP26779. Positions 60-140, 195-273, 312-390, 406-485.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

STRINGi9913.ENSBTAP00000044260.

Proteomic databases

PaxDbiP26779.
PeptideAtlasiP26779.
PRIDEiP26779.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

GeneIDi281433.
KEGGibta:281433.

Organism-specific databases

CTDi5660.

Phylogenomic databases

eggNOGiKOG1340. Eukaryota.
ENOG410XSI5. LUCA.
HOGENOMiHOG000049216.
HOVERGENiHBG002617.
InParanoidiP26779.
KOiK12382.
OrthoDBiEOG7ZSHSC.
TreeFamiTF316942.

Family and domain databases

Gene3Di1.10.225.10. 4 hits.
InterProiIPR003119. SAP_A.
IPR007856. SapB_1.
IPR008138. SapB_2.
IPR008373. Saposin.
IPR011001. Saposin-like.
IPR021165. Saposin_chordata.
IPR008139. SaposinB_dom.
[Graphical view]
PfamiPF02199. SapA. 2 hits.
PF05184. SapB_1. 4 hits.
PF03489. SapB_2. 4 hits.
[Graphical view]
PIRSFiPIRSF002431. Saposin. 1 hit.
PRINTSiPR01797. SAPOSIN.
SMARTiSM00162. SAPA. 2 hits.
SM00741. SapB. 4 hits.
[Graphical view]
SUPFAMiSSF47862. SSF47862. 4 hits.
PROSITEiPS51110. SAP_A. 2 hits.
PS50015. SAP_B. 4 hits.
[Graphical view]
ProtoNetiSearch...

Publicationsi

« Hide 'large scale' publications
  1. "RT-PCR cloning of bovine prosaposin."
    Azuma N., Yoshida K.
    Submitted (JAN-2000) to the EMBL/GenBank/DDBJ databases
    Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORMS 1 AND 2), VARIANT ARG-127.
    Tissue: Mammary gland.
  2. NIH - Mammalian Gene Collection (MGC) project
    Submitted (SEP-2005) to the EMBL/GenBank/DDBJ databases
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM 2).
    Strain: Hereford.
    Tissue: Heart ventricle.
  3. "Saposin-C from bovine spleen; complete amino acid sequence and relation between the structure and its biological activity."
    Sano A., Mizuno T., Kondoh K., Hineno T., Ueno S., Kakimoto Y., Morita N.
    Biochim. Biophys. Acta 1120:75-80(1992) [PubMed] [Europe PMC] [Abstract]
    Cited for: PROTEIN SEQUENCE OF 312-391.
    Tissue: Spleen.

Entry informationi

Entry nameiSAP_BOVIN
AccessioniPrimary (citable) accession number: P26779
Secondary accession number(s): Q2HJG9, Q9N2G4
Entry historyi
Integrated into UniProtKB/Swiss-Prot: August 1, 1992
Last sequence update: October 3, 2006
Last modified: July 6, 2016
This is version 127 of the entry and version 3 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.