Selective alterations in presynaptic cytomatrix protein organization induced by calcium and other divalent cations that modulate exocytosis.
Selective alterations in presynaptic cytomatrix protein organization induced by calcium and other divalent cations that modulate exocytosis.
复制标题
由钙和其他调节胞吐作用的二价阳离子诱导的突触前细胞基质蛋白质组织的选择性改变。
DOI：
10.1111/j.1471-4159.1990.tb01224.x
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发表时间：
1990
影响因子：
4.7
通讯作者：
Garner,JA
中科院分区：
文献类型：
--
作者：
Garner,JA
Rises in intracellular calcium cause several events of physiological significance, including the regulated release of neuronal transmitters. In this study, the effects of divalent cations on the structural organization of cytomatrix in presynaptic terminals was examined. [35S]Methionine‐radiolabeled guinea pig retinal ganglion cell cytomatrix proteins were axonally transported [in slow component b (SCb) of axonal transport] to the neuron terminals in the superior colliculus. When the peak of radiolabeled cytomatrix proteins reached the terminals, synaptosomes containing the radiolabeled cytomatrix proteins were prepared. Approximately 40% of each SCb protein was soluble after hypoosmotic lysis of the radiolabeled synaptosomes in the presence of divalent cation chelators. Lysis of synaptosomes in the presence of calcium ions over a range of concentrations, however, caused a dramatic decrease in solubility of the presynaptic SCb proteins. The cytoplasmic effects may result from a calcium‐dependent condensation of cytoplasm around presynaptic terminal membrane systems. There are two major presynaptic SCb proteins (at 60 and 35 kDa), that exhibited exceptional behavior: they remained as soluble in the presence of calcium as under control conditions, suggesting that they were relatively unaffected by the mechanism causing the decrease in SCb protein solubility. Also examined were the effects of other alkaline earth and transition metal divalent cations on the presynaptic SCb proteins.
