Crystal structure of human saposin C dimer in an open conformation.[1]
Identifiers
Symbol
SapB_1
Pfam
PF05184
InterPro
IPR007856
PROSITE
PDOC50015
Available protein structures:
Pfam
structures / ECOD
PDB
RCSB PDB; PDBe; PDBj
PDBsum
structure summary
Saposin-like type B, region 2 (SapB2)
Identifiers
Symbol
SapB_2
Pfam
PF03489
InterPro
IPR008138
PROSITE
PDOC50015
CATH
1qdmC03
SCOP2
1nkl / SCOPe / SUPFAM
OPM superfamily
76
OPM protein
1sn6
Available protein structures:
Pfam
structures / ECOD
PDB
RCSB PDB; PDBe; PDBj
PDBsum
structure summary
The saposin domains refers to two evolutionally-conserved protein domains found in saposin and related proteins (SAPLIP). Saposins are small lysosomal proteins that serve as activators of various lysosomal lipid-degrading enzymes. They probably act by isolating the lipid substrate from the membrane surroundings, thus making it more accessible to the soluble degradative enzymes. All mammalian saposins are synthesized as a single precursor molecule (prosaposin) which contains four Saposin-B domains, yielding the active saposins after proteolytic cleavage, and two Saposin-A domains that are removed in the activation reaction.[2]
The Saposin-B domains also occur in other proteins, most of them playing a role in interacting with membranes.[2][3][4]
^PDB: 2qyp, Rossmann M, Schultz-Heienbrok R, Behlke J, Remmel N, Alings C, Sandhoff K, Saenger W, Maier T (May 2008). "Crystal structures of human saposins C and D: implications for lipid recognition and membrane interactions". Structure. 16 (5): 809–17. doi:10.1016/j.str.2008.02.016. PMID 18462685.
^ abMunford RS, Sheppard PO, O'Hara PJ (August 1995). "Saposin-like proteins (SAPLIP) carry out diverse functions on a common backbone structure". Journal of Lipid Research. 36 (8): 1653–63. doi:10.1016/S0022-2275(20)41485-3. PMID 7595087.
^Ponting CP (February 1994). "Acid sphingomyelinase possesses a domain homologous to its activator proteins: saposins B and D". Protein Science. 3 (2): 359–61. doi:10.1002/pro.5560030219. PMC 2142785. PMID 8003971.
^Tschopp J, Hofmann K (March 1996). "Cytotoxic T cells: more weapons for new targets?". Trends in Microbiology. 4 (3): 91–4. doi:10.1016/0966-842X(96)81522-8. PMID 8868085.
and 12 Related for: Saposin protein domain information
The saposindomains refers to two evolutionally-conserved proteindomains found in saposin and related proteins (SAPLIP). Saposins are small lysosomal...
saposins A, B, C, and D. Saposin is an acronym for Sphingolipid Activator PrO[S]teINs. Each domain of the precursor protein is approximately 80 amino...
sections of the protein are removed; this relationship is found between saposin and swaposin. Fission and fusion occurs when partial proteins fuse to form...
"Structure of Human Acid Sphingomyelinase Reveals the Role of the SaposinDomain in Activating Substrate Hydrolysis". Journal of Molecular Biology. 428...
requires the activating proteinSaposin C as well as negatively charged lipids for maximal catalytic activity. The role of Saposin C is not known; however...
of the lung. Humans and animals born with a congenital absence of the saposin family SP-B experience intractable respiratory failure whereas those born...
similarity 3 (FAM3) family and encodes a secreted protein with a GG domain. A change in expression of this protein has been noted in pancreatic cancer-derived...
galactosylceramidase. In rare cases, it may be caused by a lack of active saposin A (a derivative of prosaposin). The buildup of unmetabolized lipids adversely...
E3-ubiquitin ligase Mylip/Idol and the Canopy2 (Cnpy2)/Mylip-interacting saposin-like protein (Msap)". The Journal of Biological Chemistry. 287 (16): 12602–11...
prosaposin, which is cleaved into saposin peptides in the lysosome, and cathepsin D, the primary protease involved in protein aggregate break down. GRN mutation...
whereby ASMase exists in equilibrium between open and closed forms of the saposindomain. In the absence of membranes, closed ASMasesap decoupled from ASMasecat...
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