PSAP - Prosaposin - human protein (Function)
 
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PSAP »  Prosaposin
 
Protein also known as:  Proactivator polypeptide. Cleaved into:  Saposin-A; Saposin-B; Saposin-B-Val; Saposin-C; Saposin-D.
Gene name:  PSAP
Entry whose protein(s) existence is based on evidence at protein level
extend overview
1 103 3
GENE REF ISO

Function

 show evidences
Overview 
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.  
2
  • CuratedUniProtKB
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.  
2
  • CuratedUniProtKB
Saposin-D is a specific sphingomyelin phosphodiesterase activator (EC 3.1.4.12).  
2
  • CuratedUniProtKB
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.  
2
  • CuratedUniProtKB
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.  
2
  • CuratedUniProtKB
According to TCDB this is a transporter from family:
the amoebapore (amoebapore) family  1.C.35.2.1  
GO molecular function 
Enzyme activator activitydefinition[GO:0008047]  
1
  • TASPINC
Lipid bindingdefinition[GO:0008289]  
1
  • TASPINC
GO biological process 
Cellular response to organic substancedefinition[GO:0071310] silver  
  • IEAOrtholog Compara
Epithelial cell differentiation involved in prostate gland developmentdefinition[GO:0060742] silver  
  • IEAOrtholog Compara
Lipid transportdefinition[GO:0006869]  
1
  • TASPINC
Positive regulation of catalytic activitydefinition[GO:0043085]  
1
  • TASGOC
Prostate gland growthdefinition[GO:0060736] silver  
  • IEAOrtholog Compara
Regulation of catalytic activitydefinition[GO:0050790]  
1
  • TASGOC
Regulation of lipid metabolic processdefinition[GO:0019216] silver  
  • IEAOrtholog Compara
Regulation of MAPK cascadedefinition[GO:0043408] silver  
  • IEAOrtholog Compara
Pathways 
According to KEGG, this protein belongs to the following pathway:
Lysosome  hsa04142+5660  
According to Reactome, this protein belongs to the following pathways:
Hemostasis  REACT_604  
Metabolism  REACT_111217  
Note 
Saposin-B co-purifies with 1 molecule of phosphatidylethanolamine.  
  • CuratedUniProtKB
 

Keywords

Biological process 
Lipid metabolism  definition   [KW-0443]
Sphingolipid metabolism  definition   [KW-0746]
Technical term 
Reference proteome  definition   [KW-1185]
 

Further external links

GeneWiki: Prosaposin
GenomeRNAi: 5660
PRO: PR:P07602