Cover Picture: Saposin B Binds the Lipofuscin Bisretinoid A2E and Prevents its Enzymatic and Photooxidation (ChemPhotoChem 6/2017)

ChemPhotoChem ◽  
2017 ◽  
Vol 1 (6) ◽  
pp. 254-254
Author(s):  
Jay Tinklepaugh ◽  
Britannia M. Smith ◽  
Yan Nie ◽  
Kelsey Moody ◽  
Kris Grohn ◽  
...  
Keyword(s):  
Saposin B

scholarly journals Saposin B binds and transfers phospholipids

2006 ◽  
Vol 47 (5) ◽  
pp. 1045-1053 ◽  
Author(s):  
Fiorella Ciaffoni ◽  
Massimo Tatti ◽  
Alessandra Boe ◽  
Rosa Salvioli ◽  
Arvan Fluharty ◽  
...  
Keyword(s):  
Saposin B

scholarly journals The lipid transfer protein Saposin B does not directly bind CD1d for lipid antigen loading

2019 ◽  
Vol 4 ◽  
pp. 117
Author(s):  
Maria Shamin ◽  
Tomasz H. Benedyk ◽  
Stephen C. Graham ◽  
Janet E. Deane
Keyword(s):  
Lipid Transfer Protein ◽  
Direct Interaction ◽  
Lipid Binding ◽  
Lipid Transfer ◽  
Binding Assays ◽  
Lipid Transfer Proteins ◽  
Lipid Antigens ◽  
Saposin B ◽  
Protein Components ◽  
Lipid Loading

Background: Lipid antigens are presented on the surface of cells by the CD1 family of glycoproteins, which have structural and functional similarity to MHC class I molecules. The hydrophobic lipid antigens are embedded in membranes and inaccessible to the lumenal lipid-binding domain of CD1 molecules. Therefore, CD1 molecules require lipid transfer proteins for lipid loading and editing. CD1d is loaded with lipids in late endocytic compartments, and lipid transfer proteins of the saposin family have been shown to play a crucial role in this process. However, the mechanism by which saposins facilitate lipid binding to CD1 molecules is not known and is thought to involve transient interactions between protein components to ensure CD1-lipid complexes can be efficiently trafficked to the plasma membrane for antigen presentation. Of the four saposin proteins, the importance of Saposin B (SapB) for loading of CD1d is the most well-characterised. However, a direct interaction between CD1d and SapB has yet to be described. Methods: In order to determine how SapB might load lipids onto CD1d, we used purified, recombinant CD1d and SapB and carried out a series of highly sensitive binding assays to monitor direct interactions. We performed equilibrium binding analysis, chemical cross-linking and co-crystallisation experiments, under a range of different conditions. Results: We could not demonstrate a direct interaction between SapB and CD1d using any of these binding assays. Conclusions: This work establishes comprehensively that the role of SapB in lipid loading does not involve direct binding to CD1d. We discuss the implication of this for our understanding of lipid loading of CD1d and propose several factors that may influence this process.

scholarly journals Altered autophagy in the mice with a deficiency of saposin A and saposin B

Autophagy ◽  
2013 ◽  
Vol 9 (7) ◽  
pp. 1115-1116 ◽  
Author(s):  
Ying Sun ◽  
Gregory A. Grabowski
Keyword(s):  
Saposin B

scholarly journals Coenzyme Q10-Binding/Transfer Protein Saposin B also Binds γ-Tocopherol

2008 ◽  
Vol 43 (2) ◽  
pp. 95-100 ◽  
Author(s):  
GuangZhi Jin ◽  
Ryo Horinouchi ◽  
Tomofumi Sagawa ◽  
Nobutsune Orimo ◽  
Hiroshi Kubo ◽  
...  
Keyword(s):  
Coenzyme Q10 ◽  
Transfer Protein ◽  
Saposin B

scholarly journals Cloning, expression and map assignment of chicken prosaposin

1998 ◽  
Vol 330 (1) ◽  
pp. 321-327 ◽  
Author(s):  
Norihiro AZUMA ◽  
Hee-Chan SEO ◽  
Øystein LIE ◽  
Qiang FU ◽  
M. Robert GOULD ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Mammalian Species ◽  
Three Dimensional ◽  
Glycosylation Site ◽  
Amino Acid Sequences ◽  
Predicted Amino Acid Sequence ◽  
Chicken Brain ◽  
Saposin C ◽  
Saposin B

Prosaposin is the precursor of four small glycoproteins, saposins A-D, that activate lysosomal sphingolipid hydrolysis. A full-length cDNA encoding prosaposin from chicken brain was isolated by PCR. The deduced amino acid sequence predicted that, similarly to human and other mammalian species studied, chicken prosaposin contains 518 residues, including four domains that correspond to saposins A-D. There was 59% identity and 76% similarity of human and chicken prosaposin amino acid sequences. The basic three-dimensional structures of these saposins is predicted to be similar on the basis of the conservation of six cysteine residues and an N-glycosylation site. Identity of amino acid sequences was higher among saposins A, B and D than in saposin C. The predicted amino acid sequence of saposin B matched exactly that of purified chicken saposin B protein. The chicken prosaposin gene was mapped to a single locus, PSAP, in chicken linkage group E11C10 and is closely linked to the ACTA2 locus. This confirms the homology between chicken and human prosaposins and defines a new conserved segment with human chromosome 10q21-q24.

Preparation of the Cerebroside Sulfate Activator (CSAct or Saposin B) from Human Urine

1999 ◽  
Vol 68 (3) ◽  
pp. 391-403 ◽  
Author(s):  
Arvan L Fluharty ◽  
Claudio Lombardo ◽  
Andrew Louis ◽  
Richard L Stevens ◽  
Julian Whitelegge ◽  
...  
Keyword(s):  
Human Urine ◽  
Cerebroside Sulfate ◽  
Saposin B

scholarly journals Exploring the Multiligand Binding Specificity of Saposin B Reveals Two Binding Sites

ACS Omega ◽  
2017 ◽  
Vol 2 (10) ◽  
pp. 7141-7145 ◽  
Author(s):  
Jay Tinklepaugh ◽  
Britannia M. Smith ◽  
Etta Hanlon ◽  
Chloe Zubieta ◽  
Fadi Bou-Abdallah ◽  
...  
Keyword(s):  
Binding Sites ◽  
Binding Specificity ◽  
Saposin B
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