Distinct Roles of Calcineurin-Nuclear Factor of Activated T-Cells and Protein Kinase A-cAMP Response Element-Binding Protein Signaling in Presynaptic Differentiation
Distinct Roles of Calcineurin-Nuclear Factor of Activated T-Cells and Protein Kinase A-cAMP Response Element-Binding Protein Signaling in Presynaptic Differentiation
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DOI：
10.1523/jneurosci.3738-04.2005
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发表时间：
2005-03
期刊：
影响因子：
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通讯作者：
Tomoyuki Yoshida;M. Mishina
中科院分区：
文献类型：
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作者：
Tomoyuki Yoshida;M. Mishina
突触囊泡的积累和形态学变化是突触发生过程中轴突终末分化的特征。为了研究协调突触分子形成成熟的突触前末梢的调控机制，我们在体内观察了斑马鱼嗅感觉神经元的单个轴突末梢，并研究了神经元特异性基因操作对轴突末梢分化的影响。囊泡相关膜蛋白2（VAMP 2）增强的绿色荧光蛋白（EGFP）融合蛋白显示的突触囊泡逐渐在轴突终末聚集，而GAP 43与EGFP融合蛋白显示的轴突终末从受精后50 h（hpf）到84 h（hpf）从复杂的有丝状伪足的形状重塑为简单的无丝状伪足的形状。显性负性蛋白激酶A（PKA）或cAMP反应元件结合蛋白（CREB）的表达抑制突触形成过程中轴突终末的VAMP 2-EGFP点的形成。一致地，组成型活性PKA或CREB刺激VAMP 2-EGFP斑点形成。另一方面，环孢霉素A处理或抑制活化T细胞核因子（NFAT）的活化阻止了突触发生过程中轴突终末从复杂形状到简单形状的重塑。因此，组成性活性钙调磷酸酶的表达促进了轴突终末的重塑。这些结果表明，calcineurin-NFAT信号调节轴突终末重塑，PKA-CREB信号控制突触囊泡的积累。
Synaptic vesicle accumulation and morphological changes are characteristic features of axon terminal differentiation during synaptogenesis. To investigate the regulatory mechanism that orchestrates synaptic molecules to form mature presynaptic terminals, we visualized a single axon terminal of zebrafish olfactory sensory neurons in vivo and examined the effects of the neuron-specific gene manipulations on the axon terminal differentiation. Synaptic vesicles visualized with vesicle-associated membrane protein 2 (VAMP2)-enhanced green fluorescent protein (EGFP) fusion protein gradually accumulated in axon terminals, whereas the axon terminals visualized with GAP43 fused with EGFP remodeled from complex shapes with filopodia to simple shapes without filopodia from 50 h postfertilization (hpf) to 84 hpf. Expression of dominant-negative protein kinase A (PKA) or cAMP response element-binding protein (CREB) suppressed the VAMP2-EGFP punctum formation in axon terminals during synaptogenesis. Consistently, constitutively active PKA or CREB stimulated VAMP2-EGFP puncta formation. On the other hand, cyclosporine A treatment or suppression of nuclear factor of activated T cells (NFAT) activation prevented the axon terminal remodeling from complex to simple shapes during synaptogenesis. Consistently, expression of constitutively active calcineurin accelerated the axon terminal remodeling. These results suggest that calcineurin-NFAT signaling regulates axon terminal remodeling, and PKA-CREB signaling controls synaptic vesicle accumulation.