Abstract
We previously demonstrated monitoring and imaging of intracellular temperature based on a fluorescent polymeric thermometer and quantitative fluorescence imaging techniques, showing non-homogeneous temperature variation in steady-state and unsteady state living cells. Here, we have investigated intracellular thermogenesis to understand the physiological significance of temperature change on cell functions. By heating cells with an external infra-red laser, we were able to provoke quantitative heating of localized area (〜1 μm^2) of cells. This method of manipulating intracellular temperature allowed the observation of heat diffusion in living cells and cell response to heat shock. In particular, we have investigated intracellular temperature change in stressed cells and revealed that local thermogenesis in cells serves to initiate stress granule (SG) formation, where mRNAs are accumulated and translation is repressed. Our results of imaging and manipulating intracellular temperature unveiled a novel principle of cell biology that intracellular local temperature change drives cell functions.
