In eukaryotic cells, proteins are targeted to their final subcellular locations with precise timing. A key underlying mechanism is the active transport of cognate mRNAs, which in many systems can be linked intimately to membrane trafficking. A prominent example is the long-distance endosomal transport of mRNAs and their local translation. Here, we describe current highlights of fundamental mechanisms of the underlying transport process as well as of biological functions ranging from endosperm development in plants to fungal pathogenicity and neuronal processes. Translation of endosome-associated mRNAs often occurs at the cytoplasmic surface of endosomes, a process that is needed for membrane-assisted formation of heteromeric protein complexes and for accurate subcellular targeting of proteins. Importantly, endosome-coupled translation of mRNAs encoding mitochondrial proteins, for example, seems to be particularly important for efficient organelle import and for regulating subcellular mitochondrial activity. In essence, these findings reveal a new mechanism of loading newly synthesised proteins onto endocytic membranes enabling intimate crosstalk between organelles. The novel link between endosomes and mitochondria adds an inspiring new level of complexity to trafficking and organelle biology.

中文翻译：

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将 mRNA 的运输和翻译与内涵体和线粒体联系起来


在真核细胞中，蛋白质以精确的时间定位到其最终的亚细胞位置。一个关键的潜在机制是同源 mRNA 的主动转运，在许多系统中它可以与膜运输密切相关。一个突出的例子是 mRNA 的长距离内体转运及其局部翻译。在这里，我们描述了基础运输过程的基本机制以及从植物胚乳发育到真菌致病性和神经元过程的生物功能的当前亮点。内体相关 mRNA 的翻译通常发生在内体的细胞质表面，这是膜辅助异聚蛋白复合物形成和准确的蛋白质亚细胞靶向所需的过程。重要的是，编码线粒体蛋白的 mRNA 的内体偶联翻译似乎对于有效的细胞器输入和调节亚细胞线粒体活性特别重要。从本质上讲，这些发现揭示了一种将新合成的蛋白质加载到内吞膜上的新机制，从而实现细胞器之间的密切串扰。内体和线粒体之间的新颖联系为运输和细胞器生物学增加了令人鼓舞的新水平的复杂性。