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Saposins utilize two strategies for lipid transfer and CD1 antigen presentation.

Authors :
León, Luis
Tatituri, Raju V. V.
Grenha, Rosa
Ying Sun
Barral, Duarte C.
Minnaard, Adruaan J.
Bhowruth, Veemal
Veerapen, Natacha
Besra, Gurdyal S.
Kasmar, Anne
Wei Peng
Branch Moody, D.
Grabowski, Gregory A.
Brenner, Michael B.
Source :
Proceedings of the National Academy of Sciences of the United States of America. 3/20/2012, Vol. 109 Issue 12, p4357-4364. 8p.
Publication Year :
2012

Abstract

Transferring lipid antigens from membranes into CD1 antigen-presenting proteins represents a major molecular hurdle necessary for T-cell recognition. Saposins facilitate this process, but the mechanisms used are not well understood. We found that saposin B forms soluble saposin protein-lipid complexes detected by native gel electrophoresis that can directly load CD1 proteins. Because saposin B must bind lipids directly to function, we found it could not accommodate long acyl chain containing lipids. In contrast, saposin C facilitates CD1 lipid loading in a different way. It uses a stable, membrane-associated topology and was capable of loading lipid antigens without forming soluble saposin-lipid antigen complexes. These findings reveal how saposins use different strategies to facilitate transfer of structurally diverse lipid antigens. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00278424
Volume :
109
Issue :
12
Database :
Academic Search Index
Journal :
Proceedings of the National Academy of Sciences of the United States of America
Publication Type :
Academic Journal
Accession number :
73945370
Full Text :
https://doi.org/10.1073/pnas.1200764109