At the ASBMB 2011 annual meeting, the "Lipid and Membrane Metabolism" theme will cover phosphoinositides, sphingolipids, phospholipases D and neutral lipids. The meeting will be held April 9-13, 2011, in Washington, D.C. (Titled "Lipids Take Center Stage" in print version.)
|Vytas A. Bankaitis
||Teresa M. Dunn
Distinct chemical families of lipids endow divergent biophysical properties to the membranes in which they reside. Thus, lipid distribution between various intracellular organelles must be properly regulated to insure appropriate membrane function. Many different classes of lipids also are known to serve as metabolic precursors to various second messengers or as signaling molecules in their own right. Because lipid signaling pathways interface with highly interdigitated networks of biological processes, diverse territories of intracellular lipid metabolism and trafficking need to be tightly coordinated. The 2011 American Society for Biochemistry and Molecular Biology annual meeting “Lipid and Membrane Metabolism” theme focuses on new progress regarding how the metabolism, trafficking, organization and biological functions of major lipid classes are coordinated. The theme consists of the following four sessions.
Phosphoinositides are essential signaling lipids that modulate a diverse set of cellular processes. Phosphoinositide metabolism is subject to exquisite spatial and temporal regulation both at the level of synthesis (by lipid kinases) and degradation (by phospholipases and phosphatases). Yet, many aspects of phosphoinositide function remain unclear.
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In the “Current Topics in Phosphoinositide Biology and Signaling” session, Christopher S. Burd (University of Pennsylvania School of Medicine) will discuss his new findings on the roles of phosphatidylinositol-4-phosphate (PtdIns-4-P) in Golgi retrograde trafficking pathways. Julie Brill (The Hospital for Sick Children) will describe her work on physiological functions of PtdIns-4-P production in multicellular organisms using Drosophila as an experimental model.
And, Vytas A. Bankaitis (University of North Carolina School of Medicine) will round out the session by discussing the mechanisms by which PtdIns-transfer proteins act as coincidence detectors for the coupling of disparate pathways from lipid metabolism to production of functionally privileged phosphoinositide signaling pools.
Sphingolipids facilitate the formation of membrane microdomains and act as signaling molecules that regulate a myriad of cellular processes. The “Sphingolipid Metabolism and Biological Regulation” session will feature newly described sphingolipid regulatory mechanisms.
Lipid and Membrane Metabolism
Session: Current Topics in Phosphoinositide Biology and Signaling
• Ptdlns-4-kinase Regulation of Protein Sorting in the Golgi Apparatus, Christopher S. Burd, University of Pennsylvania School of Medicine
• Phosphatidylinositol-4-phosphate Signaling in Drosophila, Julie Brill, The Hospital for Sick Children
• Coordination of Lipid Metabolism with Phosphoinositide Signaling by Phosphatidylinositol Transfer Proteins of the Sec14 Superfamily, Vytas A. Bankaitis, University of North Carolina School of Medicine
Session: Sphingolipid Metabolism and Biological Regulation
• Sphingosine Phosphate Lyase and the DNA Damage Response, Julie D. Saba, Children’s Hospital Oakland
• The Asthma-associated ORM/ORMDL Family Proteins Mediate Sphingolipid Homeostasis, Jonathan S. Weissman, Howard Hughes Medical Institute Investigator, University of California, San Francisco
• Biology and Enzymology of Sphingolipid Synthesis, Teresa M. Dunn, Uniformed Services University of the Health Sciences
Session: Phospholipase D and Phosphatidic Acid Signaling
• Chemical Biology Approaches to Defining Phosphatidic Acid Signaling Pathways, H. Alex Brown, Vanderbilt University School of Medicine
• The Role of Phospholipase D in Vesicle Fusion, Aaron Neiman, Stony Brook University
• Lipid Signaling Regulated by pH: Phosphatidic Acid as a pH Biosensor, Christopher J. R. Loewen, University of British Columbia
Session: Biology of Neutral Lipid Metabolism and Trafficking
• The Ins and Outs of Fat Metabolism: New Insights from Yeast, Sepp D. Kohlwein, University of Graz
• Intracellular Cholesterol Transport, Frederick R. Maxfield, Weill Cornell Medical College
• Intra-organelle Sterol Transfer Activity of Oxysterol Binding Proteins, Neale Ridgway, Dalhousie University
Julie D. Saba (Children’s Hospital Oakland Research Institute) will discuss her recent work on the role of sphingosine-1-phosphate lyase in DNA repair as an example of the underinvestigated problem of lipid signaling in the nucleus. The committed enzyme of sphingolipid synthesis, SPT, is also expected to be highly regulated, but the mechanisms are elusive. Jonathan S. Weissman (University of California, San Francisco) will present new insights into sphingolipid homeostasis, the role of the ORM/ORMDL family of proteins as regulators of that process and how this regulatory circuit provides new paradigms for etiologies of asthma. Finally, Teresa M. Dunn (Uniformed Services University of the Health Sciences) will describe novel stimulatory subunits of SPT that modulate acyl-CoA substrate selectivity and may hold the key to a molecular basis for the HSAN1 inherited peripheral neuropathy.
Phospholipases D (PLD) hydrolyze phosphatidylcholine (PtdCho) to phosphatidic acid (PtdOH) and choline. The potent signaling functions attributed to PtdOH, when coupled with the regulation of PLD activity by phosphoinositides, small GTPases and protein kinases, identifies these enzymes as potentially central integrators of phospholipid metabolism and signaling. Yet, the biological activities of these enzymes have been frustratingly difficult to discern— particularly in mammalian cells.
Research into this problem will be on display in the “Phospholipase D and Phosphatidic Acid Signaling” session. H. Alex Brown (Vanderbilt University School of Medicine) will describe the characterization of recently developed small molecule inhibitors of mammalian PLDs, the cellular effects associated with acute PLD inactivation and new mass spectrometry-based techniques for molecular tracking of PtdOH.
The presentations by Aaron Neiman (Stony Brook University) and Christopher J. R. Loewen (University of British Columbia) will focus on signaling roles for PtdOH. Neiman will discuss the regulation of PLD1 and the roles of PtdOH in developmentally regulated re-orientation of membrane trafficking and vesicle fusion during sporulation in yeast. Loewen will describe evidence that PtdOH plays a previously unappreciated role as a membrane pH sensor.
The recent linkage of excessive storage of triacylglycerols (TAGs) to obesity and type 2 diabetes has spurred studies that elevate lipid droplets (LDs), major TAG storage depots, to the status of an intracellular organelle.
In the “Biology of Neutral Lipid Metabolism and Trafficking” session, Sepp D. Kohlwein (University of Graz) will discuss recent evidence of an unexpected link between fatty acid and triacylglycerol metabolism and the transcriptional regulation of phospholipid synthesis.
Aberrant cholesterol transport and storage underlie many diseases, and these processes have been studied intensively for many years. Nonetheless, fundamental aspects of intracellular sterol transport and distribution remain poorly understood. Frederick R. Maxfield (Weill Cornell Medical College) will present current progress on intracellular sterol trafficking and distribution. And finally, Neale Ridgway (Dalhousie University) will discuss how the enigmatic oxysterol binding proteins coordinate sterol trafficking and metabolism.
Teresa M. Dunn (email@example.com) is a professor and chair of the department of biochemistry and molecular biology at the Uniformed Services University of the Health Sciences. Vytas A. Bankaitis (firstname.lastname@example.org) is a professor and chair of cell and developmental biology at the University of North Carolina School of Medicine.