Measurements of Calcium in Chromaffin Cell Organelles Using Targeted Aequorins.

The molecular mechanisms that mediate and regulate calcium (Ca) fluxes through the membranes of intracellular organelles play a key role in the generation and shaping of the local and global cytosolic Ca signals triggering the process of regulated exocytosis in chromaffin cells. Beyond that role, intraorganellar Ca homeostasis also regulates organelle-specific processes such as oxidative phosphorylation in mitochondria, maturation of secretory granules, or stress in the endoplasmic reticulum. In this chapter, we describe current methods to study mitochondrial, endoplasmic reticulum, and secretory vesicle calcium homeostasis in living chromaffin cells using engineered targeted aequorins.