High-Resolution Calcium Imaging Method for Local Calcium Signaling

All eukaryotic cells respond to extracellular signals in a physiologically meaningful way. For multicellular organisms, physiologically relevant cooperation is only possible, if cell-cell communication works properly. Here, the extracellular signals must be translated into intracellular signals that ultimately result in cellular responses. This process is termed signal transduction or signaling. Ca2+ signaling has been developed in almost all eukaryotic cells. The cellular components used for this highly versatile signaling system are often termed “Ca2+ toolbox”. Besides Ca2+ pumps and Ca2+-binding proteins, the Ca2+ channels that are located in the plasma membrane and intracellular membranes and the Ca2+-mobilizing second messengers are major players in shaping the four-dimensional nature of Ca2+ signals. Here, we report on methodological developments to acquire and analyze cellular Ca2+ signals with high temporal and spatial resolution with specific focus on (1) photobleaching of Ca2+ indicators at high acquisition rate, (2) determination of system noise and spatiotemporal detection limits, and (3) image processing.