To supply proteins to their vast volume, neurons localize mRNAs and ribosomes in dendrites and axons. While local protein synthesis is required for synaptic plasticity, the abundance and distribution of ribosomes and nascent proteins near synapses remain elusive. Here, we quantified the occurrence of local translation and visualized the range of synapses supplied by nascent proteins during basal and plastic conditions. We detected dendritic ribosomes and nascent proteins at single-molecule resolution using DNA-PAINT and metabolic labeling. Both ribosomes and nascent proteins positively correlated with synapse density. Ribosomes were detected at ~85% of synapses with ~2 translational sites per synapse; ~50% of the nascent protein was detected near synapses. The amount of locally synthesized protein detected at a synapse correlated with its spontaneous Ca²⁺ activity. A multifold increase in synaptic nascent protein was evident following both local and global plasticity at respective scales, albeit with substantial heterogeneity between neighboring synapses.

中文翻译：

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神经元突触可塑性过程中局部蛋白质合成的普遍性和特异性

为了为其庞大的体积提供蛋白质，神经元将 mRNA 和核糖体定位在树突和轴突中。虽然突触可塑性需要局部蛋白质合成，但突触附近的核糖体和新生蛋白质的丰度和分布仍然难以捉摸。在这里，我们量化了局部翻译的发生，并可视化了在基础和可塑条件下新生蛋白质提供的突触范围。我们使用 DNA-PAINT 和代谢标记以单分子分辨率检测树突状核糖体和新生蛋白。核糖体和新生蛋白都与突触密度呈正相关。在约 85% 的突触处检测到核糖体，每个突触约有 2 个翻译位点；在突触附近检测到约 50% 的新生蛋白质。²⁺活动。在各自尺度的局部和全局可塑性之后，突触新生蛋白的多倍增加是显而易见的，尽管相邻突触之间存在显着的异质性。