Protein mediated glycolipid transfer is inhibited FROM sphingomyelin membranes but enhanced TO sphingomyelin containing raft like membranes

A1 Originalartikel i en vetenskaplig tidskrift (referentgranskad)

Interna författare/redaktörer

Publikationens författare: Nylund M, Mattjus P
Publiceringsår: 2005
Tidskrift: BBA - Biomembranes
Tidskriftsakronym: BBA-BIOMEMBRANES
Volym: 1669
Nummer: 2
Artikelns första sida, sidnummer: 87
Artikelns sista sida, sidnummer: 94
Antal sidor: 8
ISSN: 0005-2736


The mammalian glycolipid transfer protein, GLTP, catalyzes the transfer in vitro of glycolipids between membranes. In this study we have examined on one hand the effect of the variations in the donor vesicle composition and on the other hand the effects of variations in the acceptor vesicle composition on the GLTP-catalyzed transfer kinetics of galactosylceramide between bilayer vesicles. For this purpose a resonance energy transfer assay was used, the energy donor being anthrylvinyl-galactosylceramide and the energy acceptor DiO-C-16. First, we show that the transfer of anthrylvinyl-galactosylceramide from palmitoyl-oleoyl-phosphatidylcholine donor vesicles was faster than from dipalmitoyl-phosphatidylcholine vesicles, and that there is no transfer from palmitoyl-sphingomyelin vesicles regardless of the cholesterol amount. In this setup the acceptor vesicles were always 100% palmitoyl-oleoyl-phosphatidylcholine. We also showed that the transfer in general is faster from small highly curved vesicles compared to that from larger vesicles. Secondly, by varying the acceptor vesicle composition we showed that the transfer is faster to mixtures of sphingomyelin and cholesterol compared to mixtures of phosphatidylcholines and cholesterol. Based on these experiments we conclude that the GLTP mediated transfer of anthrylvinyl-galactosylceramide is sensitive to the matrix lipid composition and membrane bending. We postulate that a tightly packed membrane environment is most effective in preventing GLTP from accessing its substrates, and cholesterol is not required to protect the glycosphingolipid in the membrane from being transferred by GLTP. On the other hand GLTP can more easily transfer glycolipids to 'lipid raft' like membranes, suggesting that the protein could be involved in raft assembly.


cholesterol, glycolipid transfer protein, glycosphingolipids, lipid rafts, phosphatidylcholine, sphingomyelin

Senast uppdaterad 2020-24-09 vid 06:03