Genetically targeted calcium sensors enhance the study of organelle function in living cells

1. Understanding the regulation of calcium (Ca2+), the most common of the mineral ions within the human body, has always been of extreme interest to physiologists. While the importance of Ca2+ in contributing to physiological events through regulation of levels has been significantly established, seldom is consideration given to the intricacies of this ion and its mechanics in producing such diverse physiological responses in different regions of the cell. 2. The present review will summarize new methodologies used in our laboratories for the study of two major intracellular organelles, mitochondria and the nucleus. These techniques are based predominantly on the use of molecular biological approaches to both create and then target protein-based sensor molecules to specific intracellular locations. 3. The regulation of Ca2+ in the mitochondria and nucleus is of particular interest to us because of the central involvement of these organelles in: (i) cardiac cell responses during ischaemia/reperfusion; and (ii) the control of gene expression, respectively.