Colchicine inhibits acetylcholine receptor stimulation of G protein GTPase activity in rat striatum.
Colchicine inhibits acetylcholine receptor stimulation of G protein GTPase activity in rat striatum.
复制标题
秋水仙碱抑制大鼠纹状体中 G 蛋白 GTP 酶活性的乙酰胆碱受体刺激。
DOI：
10.1111/bcpt.1991.69.4.259
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Aronstam,RS
中科院分区：
文献类型：
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作者：
Ravindra,R;Aronstam,RS
秋水仙碱，已知影响微管蛋白的功能，被用来描述微管蛋白在大鼠纹状体膜信号转导中的可能作用。KmGTPase活性低（EC 3.6.1）。在含有1µM未标记GTP的ATP再生缓冲液中，在37°温度下使用[γ‐32P]GTP在10µg膜蛋白中进行检测。在10和100µM浓度下，秋水仙碱对GTPase活性的抑制作用分别为18%和40%。在监测反应的所有时间点，秋水仙碱（100µM）对酶活性的抑制作用为30-40%。乙酰胆碱（ACh）以浓度依赖的方式刺激低KmGTPase活性，高达57%。乙酰胆碱刺激活性被认为反映了受体偶联换能器G蛋白催化的GTP水解。在100µM秋水仙碱存在下，乙酰胆碱刺激G蛋白GTPase活性的能力被抑制。例如，在10µM ACh时，酶活性被刺激到52%；在100µM秋水仙碱存在的情况下，10µM ACh仅刺激了33%的活性。这些结果表明，秋水仙碱通过与微管蛋白或G蛋白或两者相互作用而破坏ACh受体- G蛋白偶联。
Colchicine, which is known to influence tubulin function, was used to delineate a possible role of tubulin in signal transduction in the rat striatal membranes. Low KmGTPase activity (EC 3.6.1.‐) was assayed in 10 µg membrane protein using [γ‐32P]GTP at 37° in an ATP‐regenerating buffer containing 1 µM unlabeled GTP. At 10 and 100 µM, colchicine inhibited the GTPase activity by 18% and 40%, respectively. Colchicine (100 µM) inhibited the enzymatic activity by 30–40% at all the time points the reaction was monitored. Acetylcholine (ACh) stimulated the low KmGTPase activity in a concentration‐dependent manner, by up to 57%. ACh‐stimulated activity was accepted as reflecting GTP hydrolysis catalyzed by receptor‐coupled transducer G proteins. In the presence of 100 µM colchicine, the ability of ACh to stimulate G protein GTPase activity was inhibited. For example, at 10 µM ACh the enzyme activity was stimulated up to 52%;inthe presence of 100 µM colchicine, 10 µM ACh stimulated the activity by only up to 33%. These results suggest that colchicine disrupts ACh receptor‐G protein coupling as a result of its interaction with tubulin or G protein(s) or both.