STKE Focus Issue on Lipid Biology: Lipids, Partners in Cellular Signaling

This week's issue of Science features a special section called Lipid Biology ( ) that highlights some of the complex and intriguing roles of lipids in numerous processes, including cellular lipid homeostasis, inflammation, vesicle trafficking, angiogenesis, and developmental biology. The diverse nature of these molecules underscores the variety of signaling scenarios in which these molecules participate. This STKE Focus Issue highlights two new roles of lipids in signal transduction and also touches upon some of the themes in Science's Lipid Biology with related material from the STKE archives. We encourage you to explore this collection of material for more information on how lipids are truly at the center stage of many cellular processes. A Review by Hilgemann et al . ( ) indicates that there is no rest for phosphatidylinositol 4,5-bisphosphate (PIP2). Its many effects now include direct regulation of ion channel and transporter localization and activity within membranes. Munnik and Musgrave ( ) bring together insights on phospholipase D from mammals, yeast, and plants in a Perspective that ponders how this molecule may control vesicle transport by linking membranes to microtubules. In addition to Science's News feature by Marx ( ) about membrane microdomains, Edidin presents a Perspective ( ) and opens a Forum ([http://stke.sciencemag.org/cgi/forum-display/FORUM\_4?FORUM\_ID=FORUM_4][1]) at STKE about the controversy surrounding their characterization and the interpretation of their function, particularly in localizing signaling molecules. The importance of these membrane lipid microdomains to T cell receptor signaling is discussed in a Review by Wange ( ), who focuses on why a cytosolic molecule called LAT needs to be localized into lipid microdomains for T cell activation to occur. A Protocol by Harder and Kuhn ( ) provides instruction on how to isolate signaling complexes in lipid subdomains from native T cell plasma membranes. A Perspective by van den Heuvel ( ) recounts how specific acyltransferases were identified in the posttranslational processing of the signaling protein Hedgehog, and like the Viewpoint in Science by Ingham ( ), queries the influence of fatty acid adducts to the Hh signaling pathway. Proteins can also be modified at their amino terminus by the fatty acid myristate, and in their Perspective, de Jonge et al . ( ) discuss how the addition of this lipid to newly identified target proteins affects survival and death mechanisms in mammalian and plant cells. The mechanisms regulating the association of soluble proteins to membranes by protein motifs that recognize specific lipids. In addition to the Phox-homology (Px) domains discussed by Sato et al . ( ) in Science , a Perspective by Corvera ( ) points out that the phospholipid-binding FYVE domain is also present in proteins that regulate vesicle trafficking and may have implications for signaling that arises from endosomes. The emerging evidence that derivatives of membrane phospholipids, such as lysophospholipids, are important signaling molecules is likely due to improved methods to isolate and quantitate them. Sullard and Merrill ( ) provide a Protocol to effectively analyze this category of lipid based on tandem mass spectrometry. Finally, for those interested in lipid kinases, Cantley ([http://stke.sciencemag.org/cgi/cm/CMP_6557][2]) has supplied a Connections Map of the canonical phosphoinositide 3-kinase (PI3K) pathway, where detailed information about PI3K-regulated signaling cascades can be found. A Perspective by Okkenhaug and Vanhaesebroeck ( ) discusses the complex relationship between the subunits of PI3K. Featured in This Focus Issue on Lipid Biology Related Resources at STKE [1]: http://stke.sciencemag.org/cgi/forum-display/FORUM_4?FORUM_ID=FORUM_4 [2]: pending:yes