Formation of ceramide-enriched domains in lipid particles enhances the binding of apolipoprotein E.
We investigated the interaction between apolipoprotein E (apoE) and ceramide (CER)-enriched domains on the particles, by using lipid emulsions containing sphingomyelin (SM) or CER as model particles of lipoproteins. The sphingomyelinase (SMase)-induced aggregation of emulsion particles was prevented by apoE. CER increased the amount of apoE bound to emulsion particles. The confocal images of CER-containing large emulsions with two fluorescent probes showed three-dimensional microdomains enriched in CER. SMase also induced the formation of CER-enriched domains. We propose apoE prefers to bind on CER-enriched domains exposed on particle surface, and thus inhibits the aggregation or fusion of the particles.
Morita
Shin-ya
SY
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
Nakano
Minoru
M
Sakurai
Atsushi
A
Deharu
Yuko
Y
Vertut-Doï
Aline
A
Handa
Tetsurou
T
D001057:Apolipoproteins E / Q000737:chemistry* / Q000378:metabolism; D002518:Ceramides / Q000737:chemistry* / Q000378:metabolism; D004655:Emulsions / Q000737:chemistry / Q000378:metabolism; D005456:Fluorescent Dyes; D006801:Humans; D008055:Lipids / Q000737:chemistry*; D018613:Microscopy, Confocal; D017434:Protein Structure, Tertiary; D013108:Sphingomyelin Phosphodiesterase / Q000737:chemistry; D013109:Sphingomyelins / Q000737:chemistry*
D001057:Apolipoproteins E; D002518:Ceramides; D004655:Emulsions; D005456:Fluorescent Dyes; D008055:Lipids; D013109:Sphingomyelins; D013108:Sphingomyelin Phosphodiesterase