SnapShot: Functions of Endoplasmic Reticulum Membrane Contact Sites.

The endoplasmic reticulum (ER) consists of the nuclear envelope and a reticulated interconnected network of tubules and sheets. ER sheets are studded with ribosomes and provide the entryway for proteins into the secretory pathway. ER tubules move dynamically on microtubules and form membrane contact sites with other organelles, where membranes are tethered, but not fused. This Snapshot reviews key biological processes that take place at ER contact sites with the Golgi, endosomes, and mitochondria.