SYNAPSIN-I BUNDLES F-ACTIN IN A PHOSPHORYLATION-DEPENDENT MANNER
SYNAPSIN-I BUNDLES F-ACTIN IN A PHOSPHORYLATION-DEPENDENT MANNER
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DOI：
10.1038/326704a0
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发表时间：
1987-04-16
期刊：
影响因子：
64.8
通讯作者：
GREENGARD, P
中科院分区：
文献类型：
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作者：
BAHLER, M;GREENGARD, P
突触素I是一种神经元特异性的磷酸蛋白，定位于突触小泡1，2的细胞质表面，是环状AMP依赖性和钙/钙调蛋白依赖性蛋白激酶3-5的主要底物。在体内和体外，它的磷酸化状态可以通过各种已知影响突触功能的生理和药物操作来改变。最近的直接证据表明，它可能参与神经末梢神经递质释放的调节。在神经末梢，突触小泡嵌入细胞骨架网络，构成肌动蛋白9-11的一部分。我们在这里报道了脱磷形式的突触素I捆绑F-肌动蛋白的能力。当突触素I被cAMP依赖的蛋白激酶磷酸化时，这种结合活性降低，而当它被钙/钙调蛋白依赖的蛋白激酶II或两者同时磷酸化时，这种结合活性几乎消失。这些结果证明了突触素I与放线菌素在体外的相互作用，支持了突触素I参与突触前末端突触小泡聚集的可能性，以及突触素I的磷酸化可能参与调节突触小泡向其释放部位的移位。
Synapsin I is a neuron-specific phosphoprotein localized to the cytoplasmic surface of synaptic vesicles1,2. This phosphoprotein is a major substrate for cyclic AMP-dependent and calcium/calmodulin-dependent protein kinases3–5. Its state of phosphorylation can be altered bothin vivoandin vitroby a variety of physiological and pharmacological manipulations known to affect synaptic function6,7. Recent direct evidence suggests that it may be involved in the regulation of neurotransmitter release from the nerve terminal8. In the nerve terminal, synaptic vesicles are embedded in a cytoskeletal network, consisting in part of actin9–11. We report here the ability of the dephospho-form of synapsin I to bundle F-actin. This bundling activity is reduced when synapsin I is phosphorylated by cAMP-dependent protein kinase and virtually abolished when it is phosphorylated by calcium/calmodulin-dependent protein kinase II or by both kinases. These results, demonstrating an interaction of synapsin I with actinin vitro, support the possibility that synapsin I is involved in clustering of synaptic vesicles at the presynaptic terminal and that the phosphorylation of synapsin I may be involved in regulating the translocation of synaptic vesicles to their sites of release.