April 2010

Symposium: Biochemistry of Membrane Traffic: Secretory and Endocytic Pathways


Suzanne Pfeffer

Many scientists are carrying out outstanding biochemistry in hopes of defining the precise molecular events that drive the transport of membrane proteins from one compartment to another in eukaryotic cells. This meeting seeks to bring together those interested in understanding how molecules drive the secretory and endocytic pathways and allow them to share recent breakthroughs and discuss controversies. Unlike most research conferences, the majority of the oral presentations at this meeting will be solicited from submitted abstracts – to ensure that those who are really interested in membrane traffic will have an opportunity to contribute to what we hope will be an excellent program.

Vivek Malhotra

For the past 30 years, research has revealed many of the proteins that participate in transport vesicle formation – cargo selection, membrane curving and vesicle coating. But, there remain many pathways for which the transport carriers are unidentified and for which nothing is known about how proteins are sorted into them. In the endoplasmic reticulum, for example, a nonglycosylated, cytoplasmic viral protein recently was found to be among the most rapidly secreted proteins, suggesting that not all cargos require specific receptors for trafficking. There also is evidence that, in some cases, vesicle docking is linked directly to the vesicle formation process. These observations bring to mind questions like: How is it that vesicles form, containing not only the correct cargos, but also the necessary proteins to drive their docking and fusion? How is vesicle uncoating regulated, and where does it take place?

Many of the proteins that drive membrane traffic are cytosolic factors that are recruited coordinately to different cellular membranes to provide those membrane surfaces with distinct functionalities. We need to define the precise nature of each of these distinct membrane microdomains before we can fully understand how cells are able to sort, secrete and internalize proteins.

Biochemistry of Membrane Traffic: Secretory and Endocytic Pathways 
Oct. 28 – 31, 2010
Granlibakken Resort, Lake Tahoe, Calif.
Short talk and poster abstract deadline: July 1, 2010
Early registration deadline: July 30, 2010

Transport vesicles engage molecular motors that rely on either the actin- or microtubule-based cytoskeletons and can move in opposite directions. How do cells regulate these motors to accomplish targeted delivery of transport vesicles? How are target membranes recognized? The structures of tethering factors are beginning to become available, but almost nothing is known about how vesicles recognize and first engage their unique targets. And, despite an enormous body of work on the SNARE proteins that drive membrane fusion, little is known about how active SNARE complexes are formed and how their formation is regulated.

What is the molecular basis for the biogenesis of the Golgi apparatus, and how are large cargos, such as collagen, transported across and from these membranes? How are regulated-secretory products packaged into transport vesicles that are distinct from those carrying cell-surface receptors? How are receptors that need to be downregulated actually incorporated into the lumens of multivesicular endosomes? How is cargo sorted during the process of autophagy, and how do autophagosomes release exosomes from cells? How do pathogens hijack these processes for their survival and propogation? By defining these events in precise molecular detail, we hope to identify novel and precise targets for future intervention in a number of pathological states.

Thus, we invite all biochemists, molecular cell biologists, structural and systems biologists, proteomicists and biophysicists to join us to learn as much as we can about such an entirely underexplored, fascinating and important research area. Student and postdoctoral fellows especially are encouraged to attend.

Suzanne Pfeffer (pfeffer@stanford.edu) is a biochemistry professor at the Stanford University School of Medicine, and Vivek Malhotra (vivek.malhotra@crg.es) is at the Center for Genomic Regulation in Barcelona, Spain.

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