Saposin: Difference between revisions

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~~{{STRUCTURE_1n69| PDB~~=~~1n69 | SIZE~~=~~400| SCENE~~= |right~~|CAPTION~~=Human saposin C complex with lipid ~~molecule~~, [[~~1n69~~]] }}

== Function ==

'''Saposin''' (Sap) is a small protein which functions as activator of lipid-degrading enzymes. They act by isolating the lipid substrate from the membrane. Sap is synthesized as a precursor – prosaposin – which contain 4 SapB active domains (cleaved to saposin A,B,C and D) and 2 SapA domains which are cleaved off<ref>PMID:2001789</ref>. See also [[Lipid metabolism]].

'''Saposin''' ~~(Sap) is a small protein which functions as activator~~ of ~~lipid~~-~~degrading enzymes. They act~~ by ~~isolating the lipid substrate from the membrane. Sap is synthesized as a precursor – prosaposin – which contain 4 SapB active domains~~ and ~~2 SapA domains which are cleaved off~~. For more details see [[Molecular Playground/Saposin C]].

*'''Saposin A and C''' stimulate hydrolysis of methylumbelliferyl β-galactoside by β-glucosylceramidase and of galactocerebrocide by β-galactosylceramidase<ref>PMID:2717620</ref>. For more details see [[Molecular Playground/Saposin C]].

*'''Saposin B''' facilitates lipid binding to CD1d<ref>PMID:17372201</ref>.

*'''Saposin D''' stimulates acid ceramidase activity<ref>PMID:8203897</ref>.

~~{{TOC limit|limit~~=~~2}}~~

== Disease ==

Mutations in saposin B are autosomal recessive trait resulting in clinical metachromatic leukodystrophy<ref>PMID:17616409</ref>. Mutations in saposin D cause urinary system defects<ref>PMID:15345707</ref>.

</StructureSection>

== 3D Structures of Saposin ==

== ~~3D Structures of~~ Saposin ==

Updated on {{REVISIONDAY2}}-{{MONTHNAME|{{REVISIONMONTH}}}}-{{REVISIONYEAR}}

{{#tree:id=OrganizedByTopic|openlevels=0|

*Saposin A residues 60-143

~~===Saposin A===~~

**[[2dob]], [[4uex]] – hSapA – human

**[[4ddj]] – hSapA + LDAO

**[[7p4d]] – mSapA – mouse

**[[5nxb]] – mSapA + galactocerebrosidase

~~[[2dob]] – hSapA~~ residues 60-~~140 – human~~

*Saposin A residues 1-81

~~===Saposin B===~~

**[[6d80]] – hSapA + mitochondrial calcium uniporter

~~[[1n69]] – hSapB + lipid~~

*Saposin B

~~===Saposin C===~~

**[[1n69]] – hSapB + lipid

**[[4v2o]] – hSapB + chloroquine

~~[[1m12]], [[1sn6]] – hSapC – NMR ~~

*Saposin C

~~[[2gtg]], [[2qyp]], [[2z9a]] – hSapC residues 311-391~~

~~===Saposin D===~~

**[[1m12]], [[1sn6]] – hSapC – NMR

**[[2gtg]], [[2qyp]], [[2z9a]] – hSapC residues 311-391

~~[[3bqp]], [[3bqq]], [[2r1q]], [[2rb3]] - hSapD residues 405-484 ~~

*Saposin D

~~[[2r0r]] - hSapD residues 407-484 (mutant)~~

**[[3bqp]], [[3bqq]], [[2r1q]], [[2rb3]] - hSapD residues 405-484

**[[5u85]] - mSapD residues 438-519

}}

== References ==

[[Category:Topic Page]]

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-{{STRUCTURE_1n69|  PDB=1n69  | SIZE=400| SCENE= |right|CAPTION=Human saposin C complex with lipid molecule, [[1n69]] }}
+<StructureSection load='2dob' size='350' side='right' scene='' caption='Human saposin A complex with Ca+2 [[2dob]]'>
+== Function ==
+'''Saposin''' (Sap) is a small protein which functions as activator of lipid-degrading enzymes.  They act by isolating the lipid substrate from the membrane.  Sap is synthesized as a precursor – prosaposin – which contain 4 SapB active domains (cleaved to saposin A,B,C and D) and 2 SapA domains which are cleaved off<ref>PMID:2001789</ref>. See also [[Lipid metabolism]].
-'''Saposin''' (Sap) is a small protein which functions as activator of lipid-degrading enzymes.  They act by isolating the lipid substrate from the membrane.  Sap is synthesized as a precursor – prosaposin – which contain 4 SapB active domains and 2 SapA domains which are cleaved off.  For more details see [[Molecular Playground/Saposin C]].
+*'''Saposin A and C''' stimulate hydrolysis of methylumbelliferyl β-galactoside by β-glucosylceramidase and of galactocerebrocide by β-galactosylceramidase<ref>PMID:2717620</ref>.  For more details see [[Molecular Playground/Saposin C]].<br />
+*'''Saposin B''' facilitates lipid binding to CD1d<ref>PMID:17372201</ref>.<br />
+*'''Saposin D''' stimulates acid ceramidase activity<ref>PMID:8203897</ref>.<br />
-{{TOC limit|limit=2}}
+== Disease ==
+Mutations in saposin B are autosomal recessive trait resulting in clinical metachromatic leukodystrophy<ref>PMID:17616409</ref>. Mutations in saposin D cause urinary system defects<ref>PMID:15345707</ref>.
+</StructureSection>
+== 3D Structures of Saposin ==
-== 3D Structures of Saposin ==
+Updated on {{REVISIONDAY2}}-{{MONTHNAME|{{REVISIONMONTH}}}}-{{REVISIONYEAR}}
+{{#tree:id=OrganizedByTopic|openlevels=0|
+*Saposin A residues 60-143
-===Saposin A===
+**[[2dob]], [[4uex]] – hSapA  – human<br />
+**[[4ddj]] – hSapA + LDAO<br />
+**[[7p4d]] – mSapA – mouse<br />
+**[[5nxb]] – mSapA + galactocerebrosidase <br />
-[[2dob]] – hSapA residues 60-140 – human
+*Saposin A residues 1-81
-===Saposin B===
+**[[6d80]] – hSapA + mitochondrial calcium uniporter<br />
-[[1n69]] – hSapB + lipid
+*Saposin B
-===Saposin C===
+**[[1n69]] – hSapB + lipid<br />
+**[[4v2o]] – hSapB + chloroquine<br />
-[[1m12]], [[1sn6]] – hSapC – NMR<br />
+*Saposin C
-[[2gtg]], [[2qyp]], [[2z9a]] – hSapC residues 311-391
-===Saposin D===
+**[[1m12]], [[1sn6]] – hSapC – NMR<br />
+**[[2gtg]], [[2qyp]], [[2z9a]] – hSapC residues 311-391
-[[3bqp]], [[3bqq]], [[2r1q]], [[2rb3]] - hSapD residues 405-484<br />
+*Saposin D
-[[2r0r]] - hSapD residues 407-484 (mutant)
+**[[3bqp]], [[3bqq]], [[2r1q]], [[2rb3]] - hSapD residues 405-484<br />
+**[[5u85]] - mSapD residues 438-519<br />
+}}
+== References ==
+<references/>
 [[Category:Topic Page]]