Tbio PSAP Prosaposin

Protein Summary

Description

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. 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. Saposin-D is a specific sphingomyelin phosphodiesterase activator (EC 3.1.4.12). 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. 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. This gene encodes a highly conserved preproprotein that is proteolytically processed to generate four main cleavage products including saposins A, B, C, and D. Each domain of the precursor protein is approximately 80 amino acid residues long with nearly identical placement of cysteine residues and glycosylation sites. Saposins A-D localize primarily to the lysosomal compartment where they facilitate the catabolism of glycosphingolipids with short oligosaccharide groups. The precursor protein exists both as a secretory protein and as an integral membrane protein and has neurotrophic activities. Mutations in this gene have been associated with Gaucher disease and metachromatic leukodystrophy. Alternative splicing results in multiple transcript variants, at least one of which encodes an isoform that is proteolytically processed. [provided by RefSeq, Feb 2016]

Uniprot Accession IDs

• P07602
• P07292
• P15793
• P78538
• P78541
• P78546
• P78547
• P78558
• Q53Y86
• Q6IBQ6
• Q92739
• Q92740
• Q92741
• Q92742

Gene Name

• PSAP

Ensembl ID

• ENST00000394936
• ENSP00000378394
• ENSG00000197746

Symbol

• GLBA
• SAP1
• GLBA
• SAP1

Knowledge Table

Most Knowledge About	Knowledge Value (0 to 1 scale)
kinase perturbation	1
transcription factor perturbation	0.99
disease perturbation	0.93
protein domain	0.92
PubMedID	0.88

Protein Classes

DTO Classes

Prosaposin Receptor Gpr37 / Prosaposin Receptor Gpr37l1

IDG Development Level Summary

Tdark

These are targets about which virtually nothing is known. They do not have known drug or small molecule activities
- AND - satisfy two or more of the following criteria:

Pubmed score: 289.36   (req: < 5)

Gene RIFs: 61   (req: <= 3)

Antibodies: 414   (req: <= 50)

Tbio

These targets do not have known drug or small molecule activities
- AND - satisfy two or more of the following criteria:

Pubmed score: 289.36   (req: >= 5)

Gene RIFs: 61   (req: > 3)

Antibodies: 414   (req: > 50)

- OR - satisfy the following criterion:

Gene Ontology Terms: 28

Tchem

Target has at least one ChEMBL compound with an activity cutoff of < 30 nM - AND - satisfies the preceding conditions

Active Ligand: 0

Tclin

Target has at least one approved drug - AND - satisfies the preceding conditions

Active Drug: 0