The endoplasmic reticulum has a central role in biosynthesis of a variety of proteins and lipids.
Mitochondria generate ATP, synthesize and process numerous metabolites, and are key regulators of cell
death. The architectures of endoplasmic reticulum and mitochondria change continually via the process of
membrane fusion, fission, elongation, degradation, and renewal. These structural changes correlate with
important changes in organellar function. Both organelles are capable of moving along the cytoskeleton, thus
changing their cellular distribution. Numerous studies have demonstrated coordination and communication
between mitochondria and endoplasmic reticulum. A focal point for these interactions is a zone of close contact
between them known as the mitochondrial–associated endoplasmic reticulum membrane (MAM), which serves
as a signaling juncture that facilitates calcium and lipid transfer between organelles. Here we review the
emerging data on how communication between endoplasmic reticulum and mitochondria can modulate
organelle function and determine cellular fate.