CYCLIC-AMP ACCUMULATION IN HELA-CELLS INDUCED BY CHOLERA-TOXIN - INVOLVEMENT OF THE CERAMIDE MOIETY OF GM1 GANGLIOSIDE
CYCLIC-AMP ACCUMULATION IN HELA-CELLS INDUCED BY CHOLERA-TOXIN - INVOLVEMENT OF THE CERAMIDE MOIETY OF GM1 GANGLIOSIDE
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DOI：
10.1042/bj2710107
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发表时间：
1990-10-01
影响因子：
4.1
通讯作者：
TETTAMANTI, G
中科院分区：
文献类型：
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作者：
MASSERINI, M;PALESTINI, P;TETTAMANTI, G
通过在天然神经节苷脂或携带高度同质长链碱基部分（从天然 GM1 中分离出来）的分子种类存在下孵育细胞，研究了神经酰胺组成对 GM1 与 HeLa 细胞结合率的影响。事实证明，携带不饱和 C18 长链碱基部分的 GM1 神经节苷脂种类具有最快的缔合速率，而携带 20 个碳原子的饱和种类则具有最慢的缔合速率。通过与各种神经节苷脂种类一起孵育使GM1细胞含量增加（65倍）后，将细胞与霍乱毒素一起孵育并监测环AMP积累的时间过程。富含各种分子种类的细胞之间在环 AMP 积累之前的滞后时间的持续时间上发现了显着差异，不饱和 C18 种类显示出最短的滞后时间。此外，当 C18:1-GM1 物种存在时，与霍乱毒素孵育给定时间后积累的环 AMP 量显着高于天然 GM1。使用探针 1,3-二苯基己三烯进行的荧光各向异性实验表明，GM1 神经节苷脂神经酰胺部分也改变了宿主细胞膜的流动性。
The influence of ceramide composition on the rate of GM1 association to HeLa cells has been investigated by incubating the cells in the presence of either native ganglioside or molecular species carrying highly homogenous long chain base moieties, fractionated from native GM1. The GM1 ganglioside species carrying the unsaturated C18 long chain base moiety proved to have the fastest rate of association, whereas the saturated species carrying 20 carbon atoms had the slowest rate. After having increased the GM1 cell content (65-fold) by incubation with the various ganglioside species, the cells were incubated with cholera toxin and the time course of cyclic AMP accumulation was monitored. Remarkable differences among cells enriched with the various molecular species were found in the duration of the lag time preceding the accumulation of cyclic AMP, the shortest being displayed by the unsatured C18 species. Moreover, the amount of cyclic AMP accumulated after a given time of incubation with cholera toxin was significantly higher when the C18:1-GM1 species was present than with native GM1. Fluorescence anisotrophy experiments, carried out using the probe 1,3-diphenylhexatriene, show that the GM1 ganglioside ceramide moiety was also modifying the cell membrane fluidity of the host.