Fife, a Drosophila Piccolo-RIM Homolog, Promotes Active Zone Organization and Neurotransmitter Release
Fife, a Drosophila Piccolo-RIM Homolog, Promotes Active Zone Organization and Neurotransmitter Release
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DOI：
10.1523/jneurosci.3267-12.2012
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发表时间：
2012-11-28
影响因子：
5.3
通讯作者：
O'Connor-Giles, Kate M.
中科院分区：
文献类型：
--
作者：
Bruckner, Joseph J.;Gratz, Scott J.;O'Connor-Giles, Kate M.
神经元之间的交流依赖于神经递质在被称为活跃区（AZs）的特殊部位的精确协调释放。由活性区细胞基质（CAZ）组成的少量支架蛋白和细胞骨架蛋白被认为组织了AZs的结构和功能特性。大多数CAZ蛋白在进化上是保守的，强调了所有突触的神经传递的基本相似性。然而，核心CAZ蛋白Piccolo和Bassoon一直被认为是脊椎动物独有的，这引发了关于调节突触前特性的分子机制的保守性的有趣问题。在这里，我们在无脊椎动物中鉴定了一个短笛环相关基因，并进行了分子系统发育分析，表明编码的蛋白质可能代表短笛直系同源。据此，我们发现果蝇的同系物，Fife，是神经元的，定位于突触前AZs。为了研究Fife在体内的功能，我们产生了一个缺失的Fife位点。我们发现诱发的神经递质释放在生命突变体中大大减少，生命的丧失导致运动缺陷。通过对生命突触的形态学分析，我们确定了潜在的AZ异常，包括普遍的突触前膜脱落和突触囊泡聚集减少。我们的数据证明了piccolo相关蛋白在无脊椎动物中的保守性，并确定了ife在调节AZ结构和功能中的关键作用。这些发现表明CAZ比以前认为的更保守，并且通过更简单的模型系统的遗传研究，为更全面地了解CAZ蛋白如何调节突触前结构和功能打开了大门。
Neuronal communication depends on the precisely orchestrated release of neurotransmitter at specialized sites called active zones (AZs). A small number of scaffolding and cytoskeletal proteins comprising the cytomatrix of the active zone (CAZ) are thought to organize the architecture and functional properties of AZs. The majority of CAZ proteins are evolutionarily conserved, underscoring the fundamental similarities in neurotransmission at all synapses. However, core CAZ proteins Piccolo and Bassoon have long been believed exclusive to vertebrates, raising intriguing questions about the conservation of the molecular mechanisms that regulate presynaptic properties. Here, we present the identification of a piccolo-rim-related gene in invertebrates, together with molecular phylogenetic analyses that indicate the encoded proteins may represent Piccolo orthologs. In accordance, we find that the Drosophila homolog, Fife, is neuronal and localizes to presynaptic AZs. To investigate the in vivo function of Fife, we generated a deletion of the fife locus. We find that evoked neurotransmitter release is substantially decreased in fife mutants and loss of fife results in motor deficits. Through morphological analysis of fife synapses, we identify underlying AZ abnormalities including pervasive presynaptic membrane detachments and reduced synaptic vesicle clustering. Our data demonstrate the conservation of a Piccolo-related protein in invertebrates and identify critical roles for Fife in regulating AZ structure and function. These findings suggest the CAZ is more conserved than previously thought, and open the door to a more complete understanding of how CAZ proteins regulate presynaptic structure and function through genetic studies in simpler model systems.