Differences in the domain forming properties of N-palmitoylated neutral glycosphingolipids in bilayer membranes

A1 Originalartikel i en vetenskaplig tidskrift (referentgranskad)


Interna författare/redaktörer


Publikationens författare: Maunula S, Björkqvist YJE, Slotte JP, Ramstedt B
Publiceringsår: 2007
Tidskrift: BBA - Biomembranes
Volym: 1768
Nummer: 2
Artikelns första sida, sidnummer: 336
Artikelns sista sida, sidnummer: 345


Abstrakt

We have compared the domain forming properties of three neutral acyl
chain defined glycosphingolipids differing in their head group
structures. The aim of the study was to explore if glycosphingolipids
and sterols exist in the same lateral domains in bilayer membranes and
how the structure of the head group influences the capacity of the
glycosphingolipids to colocalize with cholesterol. The
glycosphingolipids used in the study were galactosyl-, glucosyl- and
lactosylceramides with a palmitic acid in the N-linked position. Domain
formation in mixed bilayer vesicles was examined using fluorescent
reporter molecules associating with ordered domains, together with a
fluorescence quencher lipid in the disordered membrane phase. Our
results show that the glycosphingolipids studied were poor in forming
sterol-enriched domains compared to palmitoyl-sphingomyelin as detected
by cholestatrienol quenching. However, the tendency to associate with
cholesterol was clearly dependent on the carbohydrate structure of the
glycosphingolipids, also when two glycosphingolipids with different head
groups were mixed in the bilayer. All palmitoylated glycosphingolipids
associated with palmitoyl-sphingomyelin/cholesterol domains. Our results
show that the head group structures of neutral glycosphingolipids
markedly affect their domain forming properties in bilayers both with
and without cholesterol. The most striking observation being that large
differences in domain forming properties were seen even between
glucosylceramide and galactosylceramide, which differ only in the
stereochemistry of one hydroxyl group in the carbohydrate head group.


Senast uppdaterad 2019-18-09 vid 06:19