Mitochondria determine the sequential propagation of the calcium macrodomains revealed by the super-resolution calcium lantern imaging

Despite the wide application of super-resolution (SR) microscopy in biological studies of cells, the technology is rarely used to monitor functional changes in live cells. By combining fast spinning disc-confocal structured illumination microscopy (SD-SIM) with loading of cytosolic fluorescent Ca2+ indicators, we have developed an SR method for visualization of regional Ca2+ dynamics and related cellular organelle morphology and dynamics, termed SR calcium lantern imaging. In COS-7 cells stimulated with ATP, we have identified various calcium macrodomains characterized by different types of Ca2+ release from endoplasmic reticulum (ER) stores. Finally, we demonstrated various roles of mitochondria in mediating calcium signals from different sources; while mitochondria can globally potentiate the Ca2+ entry associated with store release, mitochondria also locally control Ca2+ release from the neighboring ER stores and assist in their refilling processes.