Gaffield Michael A, Betz William J
Neuroscience Program, University of Colorado Medical School, Anschutz Medical Campus, Aurora, Colorado 80045, USA.
J Neurosci. 2007 Dec 12;27(50):13691-700. doi: 10.1523/JNEUROSCI.3910-07.2007.
We measured synaptic vesicle mobility using fluorescence recovery after photobleaching of FM 1-43 [N-(3-triethylammoniumpropyl)-4-(4-(dibutylamino)styryl) pyridinium dibromide] stained mouse motor nerve terminals obtained from wild-type (WT) and synapsin triple knock-out (TKO) mice at room temperature and physiological temperature. Vesicles were mobile in resting terminals at physiological temperature but virtually immobile at room temperature. Mobility was increased at both temperatures by blocking phosphatases with okadaic acid, decreased at physiological temperature by blocking kinases with staurosporine, and unaffected by disrupting actin filaments with latrunculin A or reducing intracellular calcium concentration with BAPTA-AM. Synapsin TKO mice showed reduced numbers of synaptic vesicles and reduced FM 1-43 staining intensity. Synaptic transmission, however, was indistinguishable from WT, as was synaptic vesicle mobility under all conditions tested. Thus, in TKO mice, and perhaps WT mice, a phospho-protein different from synapsin but otherwise of unknown identity is the primary regulator of synaptic vesicle mobility.
我们在室温及生理温度下，使用FM 1-43 [N-(3-三乙铵丙基)-4-(4-(二丁基氨基)苯乙烯基)吡啶二溴化物] 对野生型 (WT) 和突触素三敲除 (TKO) 小鼠的运动神经末梢进行光漂白后的荧光恢复来测量突触囊泡的流动性。在生理温度下，囊泡在静息末梢中具有流动性，但在室温下几乎不移动。通过用冈田酸阻断磷酸酶，在两个温度下囊泡的流动性均增加；通过用星形孢菌素阻断激酶，在生理温度下囊泡的流动性降低；用Latrunculin A破坏肌动蛋白丝或用BAPTA-AM降低细胞内钙浓度对囊泡的流动性没有影响。突触素TKO小鼠的突触囊泡数量减少，FM 1-43染色强度降低。然而，突触传递与WT小鼠没有区别，在所有测试条件下突触囊泡的流动性也是如此。因此，在TKO小鼠，可能还有WT小鼠中，一种不同于突触素但身份未知的磷蛋白是突触囊泡流动性的主要调节因子。
