Calcium ions are central and ubiquitous intracellular signaling entities. The cellular calcium signaling machinery relies on ion transport proteins that are strategically positioned in membranes of different cellular compartments. Physical interactions between the plasma membrane (PM), mitochondria and the endoplasmic reticulum (ER) play key roles in generating and shaping intracellular calcium signals. Work in our lab is focused on elucidating the molecular mechanisms that generate and regulate calcium signaling in cells and on understanding their roles in cellular physiology.