Dual PDF signaling pathways reset clocks via TIMELESS and acutely excite target neurons to control circadian behavior.
Dual PDF signaling pathways reset clocks via TIMELESS and acutely excite target neurons to control circadian behavior.
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DOI：
10.1371/journal.pbio.1001810
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发表时间：
2014-03
期刊：
影响因子：
9.8
通讯作者：
Allada R
中科院分区：
文献类型：
--
作者：
Seluzicki A;Flourakis M;Kula-Eversole E;Zhang L;Kilman V;Allada R
对果蝇昼夜节律神经元的研究揭示了色素分散因子(PDF)神经肽信号通路的分叉，通过PKA独立地同步昼夜节律时钟或通过cAMP敏锐地控制神经元的兴奋性。分子生物钟通过神经网络相互连接。在果蝇中，色素分散因子(Pdf)是一种主要的网络调节因子，具有同步不同的Pdf(+)和Pdf(−)昼夜节律起搏神经元之间的分子振荡和控制起搏神经元输出的双重功能。然而，PDF发挥作用的机制尚不清楚。我们证明，基因抑制蛋白激酶A(PKA)可以复制−突变体，而激活PKA可以部分挽救PDF受体突变体。在非PDF DN1p神经元中，PKA亚单位转录也受时钟控制。为了解决PDF的核心时钟靶点，我们在PDF神经元中挽救了心律失常的per01突变体的PER。PDF神经元挽救可在PER较低的DN1p神经元中诱发时钟成分无时相(TIM)的高幅节律。完全丧失PDF或PKA抑制也会导致per01果蝇非PDF神经元中TIM水平降低。为了解决PDF如何影响起搏神经元输出的问题，我们将PDF集中应用于DN1p神经元，发现它显著地去极化并增加DN1p神经元的放电频率。令人惊讶的是，在腺苷环化酶抑制剂的存在下，这些影响会减弱，而在PKA抑制的存在下，这些作用仍然存在。我们已经为PDF重置和同步时钟的信号机制(PKA)和分子靶点(TIM)提供了证据，并证明了PDF对目标神经元的急性直接兴奋作用，以控制神经元输出。将TIM确定为PDF信号的目标表明它是细胞自主时钟、环境光和神经网络信号的多模式集成者。此外，这些数据揭示了依赖于PKA的时钟效应和依赖于PKA的输出效应的分叉。综上所述，我们的结果为PDF在时钟重置和起搏器输出中的双重功能提供了分子和细胞基础。生物钟提供了一种机制，用于预测和调整行为和生理过程，以适应环境中的24小时节律。在动物神经系统中，细胞自主的分子振荡器通过控制日常活动模式的神经网络耦合在一起。果蝇生物钟网络中一个主要的神经肽同步神经振荡器是色素分散因子(PDF)。在这里，我们确定了在昼夜节律神经元中处理PDF信号的分叉，以独立地重置分子时钟并调节神经元活动。我们证明，昼夜节律神经元中的cAMP激活的蛋白激酶A(PKA)对于许多PDF依赖行为是必要的和充分的。此外，我们发现PDF>；PDF受体>；PKA途径以永恒的时钟成分为靶标来控制分子振荡器，并且这一过程可能受到PKA节律性表达的影响。我们发现，这一途径在cAMP产生的水平上发生分裂，PDF和cAMP以不依赖于PKA的方式显著增加时钟神经元的活性。因此，PDF通过两条信号通路工作：一条通过PKA重置时钟，另一条通过cAMP精确控制活动。这些结果具有广泛的意义，因为神经肽信号保守地参与了昼夜节律神经网络中的时钟同步。
Studies in Drosophila circadian neurons reveal a bifurcation in the Pigment Dispersing Factor (PDF) neuropeptide signaling pathway, independently synchronizing circadian clocks via PKA or acutely controlling neuronal excitability via cAMP. Molecular circadian clocks are interconnected via neural networks. In Drosophila, PIGMENT-DISPERSING FACTOR (PDF) acts as a master network regulator with dual functions in synchronizing molecular oscillations between disparate PDF(+) and PDF(−) circadian pacemaker neurons and controlling pacemaker neuron output. Yet the mechanisms by which PDF functions are not clear. We demonstrate that genetic inhibition of protein kinase A (PKA) in PDF(−) clock neurons can phenocopy PDF mutants while activated PKA can partially rescue PDF receptor mutants. PKA subunit transcripts are also under clock control in non-PDF DN1p neurons. To address the core clock target of PDF, we rescued per in PDF neurons of arrhythmic per01 mutants. PDF neuron rescue induced high amplitude rhythms in the clock component TIMELESS (TIM) in per-less DN1p neurons. Complete loss of PDF or PKA inhibition also results in reduced TIM levels in non-PDF neurons of per01 flies. To address how PDF impacts pacemaker neuron output, we focally applied PDF to DN1p neurons and found that it acutely depolarizes and increases firing rates of DN1p neurons. Surprisingly, these effects are reduced in the presence of an adenylate cyclase inhibitor, yet persist in the presence of PKA inhibition. We have provided evidence for a signaling mechanism (PKA) and a molecular target (TIM) by which PDF resets and synchronizes clocks and demonstrates an acute direct excitatory effect of PDF on target neurons to control neuronal output. The identification of TIM as a target of PDF signaling suggests it is a multimodal integrator of cell autonomous clock, environmental light, and neural network signaling. Moreover, these data reveal a bifurcation of PKA-dependent clock effects and PKA-independent output effects. Taken together, our results provide a molecular and cellular basis for the dual functions of PDF in clock resetting and pacemaker output. Circadian clocks provide a mechanism for predicting and adapting behavioral and physiological processes to 24-hour rhythms in the environment. In animal nervous systems, cell-autonomous molecular oscillators are coupled via neural networks that control daily patterns of activity. A major neuropeptide synchronizing neural oscillators in the Drosophila clock network is PIGMENT DISPERSING FACTOR (PDF). Here we identify a fork in the processing of the PDF signal in circadian neurons to independently reset the molecular clock and regulate neuronal activity. We show that the cAMP-activated protein kinase A (PKA) in circadian neurons is necessary and sufficient for many PDF-dependent behaviors. In addition, we find that a PDF>PDF receptor>PKA pathway targets the clock component TIMELESS to control molecular oscillators, and that this process may be influenced by rhythmic expression of PKA. We show that this pathway splits at the level of cAMP generation, with PDF and cAMP acutely increasing the activity of clock neurons in a PKA-independent manner. Thus, PDF operates via dual signaling pathways: one via PKA to reset clocks and the other via cAMP to acutely control activity. These results have broad implications given the conserved involvement of neuropeptide signaling in synchronizing clocks in circadian neural networks.
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影响因子：
64.5
作者：
Chiu JC;Ko HW;Edery I
通讯作者：
Edery I
影响因子：
5.3
作者：
Harrisingh, Marie C.;Wu, Ying;Nitabach, Michael N.
通讯作者：
Nitabach, Michael N.
影响因子：
64.8
作者：
Grima, B;Chèlot, E;Rouyer, F
通讯作者：
Rouyer, F
DOI：
10.1002/cne.22311
发表时间：
2010-06-01
期刊：
The Journal of comparative neurology
影响因子：
--
作者：
Im SH;Taghert PH
通讯作者：
Taghert PH
影响因子：
18.2
作者：
Allada R;Chung BY
通讯作者：
Chung BY