抄録
Revealing spatiotemporal aspects of cellular signalling molecules is one of the major challenges to current biomedical sciences. We developed new fluorescent indicators to monitor signalling molecules upstream and downstream of intracellular Ca2+ signals within living cells. Using the indicators we have clarified important cellular mechanisms, and some of these are listed below. Imaging of inositol 1,4,5-trisphosphate (IP3) concentration changes within fine dendrites of cerebellar Purkinje cells identified robust cross talk between metabotropic and ionotropic glutamate receptors for the generation of IP3 signals. Nitric oxide (NO) generation at the parallel fiber-Purkinje cell synapse was imaged and a NO- and frequency-dependent synaptic plasticity was identified. Using organelle-targeted Ca2+ indicators, we clarified the involvement of mitochondrial Ca2+ handling in the generation of Ca2+ oscillations. We generated a fluorescence energy transfer-based indicator of myosin light chain phosphorylation, which can monitor the phosphorylation state of myosin light chain within intact cells. These results demonstrate the power of fluorescent indicators in physiological studies of a variety of cell functions. These new methods may also shed light on the regulatory mechanism of smooth muscle contraction. [Jpn J Physiol 55 Suppl:S15 (2005)]
