Fluorescent sensors reveal subcellular thermal changes.

In mammals and birds, thermoregulation to conserve body temperature is vital to life. Multiple mechanisms of thermogeneration have been proposed, localized in different subcellular organelles. However, studying thermogenesis directly in intact organelles has been challenging. Visualizing patterns of thermal changes at subcellular resolution would reveal physiologically relevant spatio-temporal information, especially if this could be done in the native cellular configuration of the cell. Here we review and compare the wide variety of intracellular thermosensors currently identified. This review focuses particularly on genetically encoded sensors. It also explores the notable physiological discoveries made using these imaging methods, which are rapidly becoming indispensible to the study of thermal biology.