論文

査読有り
2006年2月

Rapid phase change of lipid microdomains in giant vesicles induced by conversion of sphingomyelin to ceramide

BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES
  • Y Taniguchi
  • ,
  • T Ohba
  • ,
  • H Miyata
  • ,
  • K Ohki

1758
2
開始ページ
145
終了ページ
153
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1016/j.bbamem.2006.02.026
出版者・発行元
ELSEVIER SCIENCE BV

To understand the role of sphingomyelinase (SMase) in the function of biological membranes, we have investigated the effect of conversion of sphingomyelin (SM) to ceramide (Cer) on the assembly of domains in giant unilamellar vesicles (GUVs). The GUVs were prepared from mixture of 1,2-dioleol-sn-glycero-3-phosphocholine (DOPC), N-palmitoly-D-erythro-sphingosine (C(16)Cer), N-palmitoyl-D-erythro-sphingosylphosphorylcholine (C16SM) and cholesterol. The amounts of DOPC, sum of C16Cer and C16SM, and cholesterol were kept constant (the ratio of these four lipids is shown as 1:X:1-X:1 (molar ratio), i.e., X is C(16)Cer/(C(16)Cer+C16SM)). Shape and distribution of domains formed in the GUVs were monitored by a fluorescent lipid, Texas Red 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (0.1 mol%). In GUVs containing low C(16)Cer (X=0 and 0.25), round-shaped domains labeled by the fluorescent lipid were present, suggesting coexistence of liquid-ordered and disordered domains. In GUVs containing intermediate Cer concentration (X=0.5), the fluorescent domain covered most of GUV Surface, which was surrounded by gel-like domains. Differential scanning calorimetry of multilamellar vesicles prepared in the presence of higher Cer concentration (X >= 0.5) suggested existence of a Cer-enriched gel phase. Video microscopy showed that the enzymatic conversion of SM to Cer caused rapid chan-e in the domain structure: several minutes after the SMase addition, the fluorescent region spread over the GUV surface, within which regions with darker contrast existed. linage-based measurement of generalized polarization (GP) of 6-dodecanoyl-2-dimethylaminonaphthalene (Laurdan), which is related to the acyl chain ordering of the lipids, was performed. Before the SMase treatment domains with high (0.65) and low (below 0.4) GP values coexisted, presumably reflecting the liquid-ordered and disordered domains; after the SMase treatment regions with intermediate GP values (0.5) and smaller regions with higher GP values (0.65) were present. Generation of Cer thus caused a phase transition from liquid-ordered and disordered phases to a gel and liquid phase. (c) 2006 Elsevier B.V. All rights reserved.

Web of Science ® 被引用回数 : 36

リンク情報
DOI
https://doi.org/10.1016/j.bbamem.2006.02.026
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000237759200002&DestApp=WOS_CPL
ID情報
  • DOI : 10.1016/j.bbamem.2006.02.026
  • ISSN : 0005-2736
  • Web of Science ID : WOS:000237759200002

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