The mechanism of action of GTP on Ca2+ efflux from rat liver microsomal vesicles.
The mechanism of action of GTP on Ca2+ efflux from rat liver microsomal vesicles.
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GTP 对大鼠肝微粒体囊泡 Ca2 流出的作用机制。
DOI：
10.1042/bj2440087
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
J. G. Comerford
中科院分区：
文献类型：
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作者：
A. Dawson;G. Hills;J. G. Comerford
1.鸟苷5 '-[γ-硫代]三磷酸（GTP[S]），如果在GTP之前加入，则阻断GTP促进的Ca 2+流出和GTP对增强肌醇1，4，5-三磷酸（IP 3）促进的Ca 2+从预载微粒体囊泡释放的作用。然而，如果在GTP之后加入GTP[S]，它不会逆转GTP促进的Ca 2+流出，也不会抑制IP 3促进的Ca 2+释放。2. GTP在增强IP 3促进的Ca 2+释放中的作用在洗涤不含添加的GTP的微粒体囊泡后保持。这种处理后，IP 3促进的Ca 2+外流的增强可以观察到在聚（乙二醇）的情况下。3.电子显微镜显示，在GTP处理的微粒体囊泡有非常大的囊泡结构，显然是由较小的囊泡融合产生的快速生产。4.在融合过程中可检测到光散射变化。5. GTP促进的Ca 2+流出和在GTP存在下观察到的IP 3促进的Ca 2+释放的增强可能归因于GTP依赖性囊泡融合。
1. Guanosine 5'-[gamma-thio]triphosphate (GTP[S]), if added before GTP, blocks both Ca2+ efflux promoted by GTP and the effect of GTP on enhancement of inositol 1,4,5-triphosphate (IP3)-promoted Ca2+ release from preloaded microsomal vesicles. If, however, GTP[S] is added after GTP, it does not reverse the Ca2+ efflux promoted by GTP, nor does it inhibit IP3-promoted Ca2+ release. 2. The effect of GTP in enhancing IP3-promoted Ca2+ release is maintained after washing the microsomal vesicles free of added GTP. After this treatment, enhancement of IP3-promoted Ca2+ efflux can be observed in the absence of poly(ethylene glycol). 3. Electron microscopy shows that during GTP treatment of microsomal vesicles there is rapid production of very large vesicular structures, apparently produced by fusion of smaller vesicles. 4. Light-scattering changes are detectable during the fusion process. 5. Both Ca2+ efflux promoted by GTP and the enhancement of IP3-promoted Ca2+ release seen in the presence of GTP can probably be attributed to GTP-dependent vesicle fusion.