Membrane lipid domains and rafts: current applications of fluorescence lifetime spectroscopy and imaging.
Membrane microdomains and their involvement in cellular processes are part of the current paradigm of biomembranes. However, a better characterization of domains, namely lipid rafts, is needed. In this review, it is shown how the use of time-resolved fluorescence, with the adequate parameters and probes, helps elucidating the type, number, fraction, composition and size of lipid phases and domains in multicomponent model systems. The determination of phase diagrams for lipid mixtures containing sphingolipids and/or cholesterol is exemplified. The use of fluorescence quenching and Förster resonance energy transfer (FRET) are also illustrated. Strategies for studying protein-induced domains are presented. The advantages of using single point microscopic decays and fluorescence lifetime imaging microscopy (FLIM) in systems with three-phase coexistence are explained. Finally, the introduction of FLIM allows studies in live cell membranes, and the nature of the microdomains observed is readily elucidated due to the information retrieved from fluorescence lifetimes.
de Almeida
Rodrigo F M
RF
Centro de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, R. Ernesto de Vasconcelos, 1749-016 Lisboa, Portugal. rodrigo.almeida@fc.ul.pt
Loura
Luís M S
LM
Prieto
Manuel
M
D002518:Ceramides / Q000737:chemistry; D002784:Cholesterol / Q000737:chemistry / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D008563:Membrane Lipids / Q000502:physiology*; D021962:Membrane Microdomains / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D013109:Sphingomyelins / Q000737:chemistry
D002518:Ceramides; D008563:Membrane Lipids; D013109:Sphingomyelins; D002784:Cholesterol