Organelle remodeling at membrane contact sites.pdfVIP

Journal of Structural Biology 196 (2016) 15–19 Contents lists available at ScienceDirect Journal of Structural Biology journal homepage: /locate/yjsbi Organelle remodeling at membrane contact sites W. Mike Henne Department of Cell Biology, UT Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390, USA article info Article history: Received 30 January 2016 Received in revised form 11 May 2016 Accepted 12 May 2016 Available online 13 May 2016 Keywords: Membrane contact site (MCS) Plasma membrane (PM) Endoplasmic Reticulum (ER) Phospholipid Endosome Mitochondria abstract Cellular organelles must execute sophisticated biological processes to persist, and often communicate with one another to exchange metabolites and information. Recent studies suggest inter-organelle membrane contact sites (MCSs) are hubs for this cellular cross-talk. MCSs also govern membrane remodeling, thus controlling aspects of organelle shape, identity, and function. Here, we summarize three emerging phenomena that MCSs appear to govern: 1) organelle identity via the non-vesicular exchange of lipids, 2) mitochondrial shape and division, and 3) endosomal migration in response to sterol traf?cking. We also discuss the role for ER-endolysosomal contact sites in cholesterol metabolism, and the potential biomedical importance this holds. Indeed, the emerging ?eld inter-organellar cross-talk promises substantial advances in the ?elds of lipid metabolism and cell signaling. ó 2016 Published by Elsevier Inc. 1. Introduction Eukaryotic cells harbor numerous membrane bound organelles, and must cope with signi?cant spatial constraints to properly contain and compartmentalize organelles ef?ciently. As a result, organelles are often in very close proximity. Even in early electron micrographs from Keith Porter and George Palade, the ability of organelles like the Endoplasmic Reticulum (ER) to physically touch mitochondria or the plasma membrane (PM) was noted, but these phenomena were generally ig