Saposin

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Saposin-like type B, region 2
Identifiers
Symbol	SapB_2
Pfam	PF03489
InterPro	IPR008138
PROSITE	PDOC50015
SCOP	1nkl
OPM family	83
OPM protein	1sn6
Available PDB structures: 1sn6A:354-388 1m12A:354-388 1n69C:238-271 1rg4A:263-277 1rg3A:263-277 1of9A:64-98 1nkl :88-122 1l9lA:104-136

Saposins are small lysosomal proteins that serve as activators of various lysosomal lipid-degrading enzymes^[1]. 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. The Saposin-B domains also occur in other proteins, many of them active in the lysis of membranes^[2]^[3].

1 Human proteins containing this domain
2 References
3 Further reading
4 External links

[edit] Human proteins containing this domain

AOAH; GNLY; Prosaposin; PSAPL1; SFTPB;

[edit] References

^ Munford RS, Sheppard PO, O Hara PJ (1995). "Saposin-like proteins (SAPLIP) carry out diverse functions on a common backbone structure". J. Lipid Res. 36 (8): 1653-1663. PMID 7595087.
^ Ponting CP (1994). "Acid sphingomyelinase possesses a domain homologous to its activator proteins: saposins B and D". Protein Sci. 3 (2): 359-361. PMID 8003971.
^ Hofmann K, Tschopp J (1996). "Cytotoxic T cells: more weapons for new targets?". Trends Microbiol. 4 (3): 91-94. PMID 8868085.