Translocation of synapsin I in response to depolarization of isolated nerve terminals.
Translocation of synapsin I in response to depolarization of isolated nerve terminals.
复制标题
突触蛋白 I 易位以响应孤立神经末梢的去极化。
DOI：
10.1073/pnas.86.20.8108
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发表时间：
1989
影响因子：
11.1
通讯作者：
Greengard,P
中科院分区：
文献类型：
--
作者：
Sihra,TS;Wang,JK;Gorelick,FS;Greengard,P
分离的神经末梢（突触体）的去极化已被证明刺激神经递质的释放，并增加磷酸化状态的一些蛋白质，包括突触蛋白I，在钙离子依赖性的方式。突触蛋白I是一种重要的神经末梢磷蛋白，与小突触囊泡的胞质表面和细胞骨架元件以磷酸化依赖的方式相互作用。在本研究中，我们发现突触体的去极化导致突触蛋白I从颗粒到胞质（可溶性）部分的快速（2-5秒）易位。突触蛋白I的这种转位与其磷酸化状态相关，并且依赖于孵育介质中Ca 2+的存在。磷酸化的可溶性突触蛋白I的化学计量比显着高于突触蛋白I的颗粒部分，在基础和去极化条件下。这些数据是一致的假设，在原位，突触蛋白I的磷酸化促进其易位从突触囊泡/细胞骨架的胞质溶胶。这种磷酸化/易位可能有助于调节神经递质的释放。
Depolarization of isolated nerve terminals (synaptosomes) has been shown to stimulate neurotransmitter release and to increase the phosphorylation state of a number of proteins, including synapsin I, in a Ca2+-dependent manner. Synapsin I, a prominent nerve terminal phosphoprotein, interacts with the cytoplasmic surface of small synaptic vesicles and with cytoskeletal elements in a phosphorylation-dependent manner. In the present study we have found that depolarization of synaptosomes resulted in a rapid (2-5 sec) translocation of synapsin I from the particulate to the cytosolic (soluble) fraction. This translocation of synapsin I correlated with its phosphorylation state and was dependent on the presence of Ca2+ in the incubation medium. The stoichiometry of phosphorylation of soluble synapsin I was considerably higher than that of synapsin I in the particulate fraction, under both basal and depolarizing conditions. These data are consistent with the hypothesis that, in situ, the phosphorylation of synapsin I promotes its translocation from synaptic vesicles/cytoskeleton to the cytosol. This phosphorylation/translocation may be instrumental in regulating the release of neurotransmitter.