April 2011

Special Symposium: Cellular traffic of lipids and calcium at membrane contact sites

Joint meeting sponsored by ASBMB and Biochemical Society will be one of the first to focus exclusively on MCSs

Tim Levine William Prinz

The exchange of information between intracellular compartments is vital for cells. There is growing evidence that this communication can occur at close contacts between organelles often called membrane contact sites. At these sites, the membranes of two organelles are closely apposed, often within about 10 nm of one another, close enough to be bridged by a single protein. MCSs have been found in all cell types and often are between the endoplasmic reticulum and a second organelle. They also have been reported between the two membranes of gram-negative bacteria and between the internal membranes of mitochondria and chloroplasts. Small molecules, including lipids and calcium ions, are exchanged at MCSs. There also are a number of instances in which an enzyme on one of the organelles at an MCS acts on a substrate on the second organelle.

We are just beginning to understand how MCSs form and function, and many fundamental questions remain. A precise understanding of the roles of MCSs has been slowed by the relatively poor molecular understanding of how these highly conserved structures are formed and how they function in cells. Until recently, there was only a single MCS for which the structural components – the proteins that bridge the organelles – were known, making it hard to attribute cellular functions to MCSs. Recently, the identities of a number of MCS components have been discovered as well as the make-up of several bridging components. This new, detailed knowledge promises to be the seed of a novel field of nonvesicular trafficking and signaling at MCSs, as there now is a sufficient base to propel the discovery of other active players and functions.

Cellular traffic of lipids and calcium at membrane contact sites
A joint meeting with the Biochemical Society
Oct. 6 – 9, 2011
Snowbird Ski and Summer Resort, Snowbird, Utah
Oral and poster abstract submission deadline: July 15, 2011
Early registration deadline: July 15, 2011

The “Cellular traffic of lipids and calcium at membrane contact sites” meeting, which is jointly sponsored by the American Society for Biochemistry and Molecular Biology and the Biochemical Society, will be one of the first to focus exclusively on MCSs. It will bring together scientists from diverse backgrounds with a common interest in nonvesicular trafficking and signaling at MCSs. In the past, people interested in signaling and molecular exchange at MCSs have tended to focus on either lipids or calcium. This meeting will allow researchers from all disciplines with a shared interest in MCSs to come together.

We have a diverse array of invited speakers, including Luca Scorrano of the University of Geneva and Benoit Kornmann of ETH Zurich, who will address the construction of bridges between organelles. Lipid transport, with an emphasis on lipid exchange mediated by lipid transfer proteins at MCSs, will be the subject of talks from several leaders in this field, including Vytas Bankaitis of the University of North Carolina School of Medicine, Shamshad Cockcroft of University College London, Dennis Voelker of National Jewish Health and Christoph Benning of Michigan State University. Tobias Meyer of Stanford University will talk about calcium signaling and calcium flows across MCSs, and Anamaris Colberg-Poley of the Children’s National Medical Center will discuss her work on virus trafficking at organelle junctions. Several talks also will be chosen from submitted abstracts.

We are very pleased to have Richard Lewis of Stanford University Medical School give the meeting’s keynote lecture. Lewis has been a pioneer in the study of calcium signaling at junctions between the endoplasmic reticulum and the plasma membrane, and he has done groundbreaking work on how calcium uptake across junctions is regulated. He also is a dynamic speaker who is sure to give an exciting talk.

The study of how organelle junctions form and function still is at an early stage, but rapid progress is occurring on many fronts. We hope to see you in Snowbird, Utah, to learn more about and participate in this exciting, emerging field.

Tim Levine (tim.levine@ucl.ac.uk) is a lecturer in cell biology at the University College London Institute of Ophthalmology. William Prinz (wp53m@nih.gov) is an investigator in the National Institute of Diabetes and Digestive and Kidney Diseases at the National Institutes of Health.

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