Vectorial channeling as a mechanism for translational control by functional prions and condensates

Xinyu Gu, Nicholas P. Schafer, P. Wolynes
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引用次数: 5

Abstract

Significance Messenger RNA (mRNA)/protein assemblies such as functional prions and condensates are involved in locally regulating translation in eukaryotic cells. The mode of regulation depends on the structure of these assemblies. We show that the vectorial processive nature of translation can couple to transport via diffusion so as to repress or activate translation depending on the structure of the RNA protein assembly. We find that multiple factors including diffusivity changes and free energy biases in the assemblies can regulate the translation rate of mRNA by changing the balance between substrate recycling and competition between mRNAs. We mainly focus on the example of CPEB, a functional prion that has been implicated in the mechanism of synaptic plasticity of neurons and in memory. Translation of messenger RNA (mRNA) is regulated through a diverse set of RNA-binding proteins. A significant fraction of RNA-binding proteins contains prion-like domains which form functional prions. This raises the question of how prions can play a role in translational control. Local control of translation in dendritic spines by prions has been invoked in the mechanism of synaptic plasticity and memory. We show how channeling through diffusion and processive translation cooperate in highly ordered mRNA/prion aggregates as well as in less ordered mRNA/protein condensates depending on their substructure. We show that the direction of translational control, whether it is repressive or activating, depends on the polarity of the mRNA distribution in mRNA/prion assemblies which determines whether vectorial channeling can enhance recycling of ribosomes. Our model also addresses the effect of changes of substrate concentration in assemblies that have been suggested previously to explain translational control by assemblies through the introduction of a potential of mean force biasing diffusion of ribosomes inside the assemblies. The results from the model are compared with the experimental data on translational control by two functional RNA-binding prions, CPEB involved in memory and Rim4 involved in gametogenesis.
载体通道作为功能朊病毒和凝聚体的翻译控制机制
在真核细胞中,信使RNA (mRNA)/蛋白组合物(如功能性朊病毒和凝聚物)参与局部调节翻译。监管模式取决于这些议会的结构。我们表明,翻译的载体过程性质可以通过扩散偶联运输,从而根据RNA蛋白组装的结构抑制或激活翻译。我们发现,包括扩散率变化和组件中的自由能偏差在内的多种因素可以通过改变底物循环和mRNA之间竞争的平衡来调节mRNA的翻译速率。我们主要关注CPEB的例子,CPEB是一种与神经元突触可塑性和记忆机制有关的功能性朊病毒。信使RNA (mRNA)的翻译是通过一系列不同的RNA结合蛋白来调节的。很大一部分rna结合蛋白含有朊病毒样结构域,形成功能性朊病毒。这就提出了朊病毒如何在转译控制中发挥作用的问题。朊病毒对树突棘翻译的局部控制被认为是突触可塑性和记忆的机制。我们展示了通过扩散和过程翻译的通道如何在高度有序的mRNA/朊病毒聚集体中以及在依赖于它们的亚结构的较不有序的mRNA/蛋白质凝聚体中合作。我们表明,翻译控制的方向,无论是抑制还是激活,取决于mRNA/朊病毒组装中mRNA分布的极性,这决定了载体通道是否可以增强核糖体的再循环。我们的模型还解决了组合物中底物浓度变化的影响,该影响先前被建议通过引入组合内核糖体的平均力偏倚扩散势来解释组合物的翻译控制。将模型结果与两种功能性rna结合朊病毒(参与记忆的CPEB和参与配子发生的Rim4)的翻译控制实验数据进行了比较。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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