Synaptic proteins and SNARE complexes are localized in lipid rafts from rat brain synaptosomes

被引:67
作者
Gil, C [1 ]
Soler-Jover, A
Blasi, J
Aguilera, J
机构
[1] Univ Autonoma Barcelona, Dept Bioquim & Biol Mol, E-08193 Barcelona, Spain
[2] Univ Autonoma Barcelona, Inst Neurociencies, E-08193 Barcelona, Spain
[3] Univ Barcelona, IDIBELL, Hosp Llobregat, Dept Biol Cellular & Anat Patol, Catalunya, Spain
关键词
exocytosis; membrane microdomains; SNARE proteins; synaptic vesicles; lipid rafts;
D O I
10.1016/j.bbrc.2005.01.111
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The biochemical characterization of the SNARE proteins present in lipid microdomains, also known as "lipid rafts," has been addressed in earlier studies, with conflicting data from different laboratories. In this study, we use rat brain synaptosomes as a model with which to examine the presence of proteins involved in exocytosis in detergent-resistant membranes (DRM), also known as lipid rafts.' By means of buoyancy analysis in sucrose gradients of Triton X-100-solubilized synaptosomes, we identified a pool of SNARE proteins (SNAP 25, syntaxin 1, and synaptobrevin2/VAMP2) significantly associated with DRM. Furthermore, Munc18, synaptophysin, and high amounts of the isoforms I and II of synaptotagmin were also found in DRM. In addition, SDS-resistant and ternperature-dependent SNARE complexes were also detected in DRM. Treatment of synaptosomes with methyl-beta-cyclodextrin resulted in persistence of the proteins present in the DRM isolated using Triton X-100, whilst strongly impairing calcium-dependent glutamate release. The results from the present work show that lipid rnicrodomains are sites where SNARE proteins and complexes are actually present, as well as important elements in the control of regulated exocytosis. (C) 2005 Elsevier Inc. All rights reserved.
引用
收藏
页码:117 / 124
页数:8
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