PSAP — Prosaposin

PSAP belongs to a gene co-expression module in 11 of 28 SCUBA cell types. Each module groups genes that rise and fall together in that cell type; the genes it shares a module with are its closest co-expression partners there.

PSAP's module in each cell type

About the gene

Function

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). 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

Human Protein Atlas · Open Targets · UniProt

Gene annotation from the Human Protein Atlas and UniProt; see sources & licences.