title: Raft domain reorganization driven by short- and long-chain ceramide: a combined AFM and FCS study.
abstract: Naturally occurring long-chain ceramides (Cer) are known to alter the lateral organization of biological membranes. In particular, they produce alterations of microdomains that are involved in several cellular processes, ranging from apoptosis to immune response. In order to induce similar biological effects, short-chain Cer are extensively used in in vivo experiments to replace their long-chain analogues. In this work, we used the combined approach of atomic force microscopy (AFM) and fluorescence correlation spectroscopy (FCS) to investigate the effect of Cer chain length in lipid bilayers composed of sphingomyelin, dioleoyl-phosphatidylcholine, and cholesterol. Our results show that only long-chain Cer, like C18 and C16, are able to segregate from the liquid-ordered phase, forming separate Cer-enriched domains. Conversely, short-chain Cer do not form a separate phase but alter the physical properties of the liquid-ordered domains, decreasing their stability and viscosity and perturbing the lipid packing. These differences may contribute to the explanation of the different physiological effects that are often observed for the long- and short-chain Cer.
authors.affiliation: Biophysics group, Biotechnologisches Zentrum (BIOTEC), Technische Universität, Tatzberg 47-51, 01307, Dresden, Germany.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Chiantia
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Kahya
authors.forename: Petra
authors.initials: P
authors.lastname: Schwille
mesh_terms: D002518:Ceramides / Q000737:chemistry*; D002784:Cholesterol / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D008560:Membrane Fluidity; D021962:Membrane Microdomains / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D010713:Phosphatidylcholines / Q000737:chemistry; D011494:Protein Kinases / Q000737:chemistry; D017434:Protein Structure, Tertiary / Q000502:physiology; D013050:Spectrometry, Fluorescence; D013109:Sphingomyelins / Q000737:chemistry; D058570:TOR Serine-Threonine Kinases; D014783:Viscosity
chemical_list: D002518:Ceramides; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D013109:Sphingomyelins; D002784:Cholesterol; D011494:Protein Kinases; D058570:TOR Serine-Threonine Kinases; C017251:1,2-oleoylphosphatidylcholine