Visualization of subcellular thermoregulation in live cells using fluorescent coiled-coil proteins

在哺乳动物和鸟类中，保持体温的体温调节对生命至关重要。已经提出了定位于不同亚细胞细胞器的多种产热机制。然而，以前的研究未能直接观察完整细胞器中的产热作用。在这里，我们已经可视化细胞内的产热通过使用荧光温度传感器，tsGFP。tsGFP的特异性靶向使得能够可视化离散细胞器中的产热，特别是棕色脂肪细胞中的线粒体和肌管中的内质网。引人注目的是，在HeLa细胞中，靶向tsGFP揭示了线粒体产热的异质性，这与电化学梯度密切相关。因此，tsGFP直接证明亚细胞热传导，并将作为强大的工具来评估体内产热。

In mammals and birds, thermoregulation to conserve body temperature is vital to life. Multiple mechanisms of thermogeneration localized in different subcellular organelles have been proposed. However, previous studies have failed to observe thermogenesis directly in intact organelles. Here, we have visualized intracellular thermogenesis by using a fluorescent thermosensor, tsGFP. Specific targeting of tsGFPs enables visualization of thermogenesis in discrete organelles, notably mitochondria in brown adipocytes and the endoplasmic reticulum in myotubes. Strikingly, in HeLa cells, targeted tsGFP reveals heterogeneity in mitochondrial thermogenesis that is well correlated with the electrochemical gradient. Thus, tsGFPs directly demonstrate subcellular thermotransduction, and will serve as powerful tools to assess thermogenesis in vivo.