Building ER-PM contacts: keeping calm and ready on alarm

It is well over half a century since contacts between organelles such as the endoplasmic reticulum (ER), mitochondria, and the plasma membrane (PM) were first observed in electron microscopy studies. Still, these early images of seemingly rare organelle interactions continue to capture the attention and curiosity of cell biologists even today. From seminal studies first proposing roles for organelle cross talk in excitable cells, the field has now expanded to cover nearly all aspects of eukaryotic cell biology, from calcium and membrane lipid transport to vesicular trafficking, cell signaling, metabolism, and homeostasis. This review highlights recent discoveries pointing to vital roles for ER-PM contacts in membrane lipid dynamics and organization.