During the past 20 years there has been a remarkable growth in the use of fluorescence in the biological sciences. Fluorescence is now a dominant methodology used extensively in biochemistry, biophysics, biotechnology, medical diagnostics, flow cytometry, DNA sequencing and genetic analysis to name a few. It is one of the most powerful methods to study protein folding, dynamics, assembly and interactions as well as membrane structure. α-Synuclein belongs to the class of intrinsically disordered proteins lacking of a well-folded structure under physiological conditions. The conversion of α-synuclein from a soluble monomer to an insoluble fibril may underlie the neurodegeneration associated with Parkinson’s disease (PD). Although the exact mechanism of α-synuclein toxicity is still unknown, it has been proposed that disturbs membrane structure, leading to increased membrane permeability and eventual cell death. This review highlights the significant role played by fluorescence techniques in unraveling the nature of interactions between α-synuclein and membranes and its implications in PD.
 J. R. Silvius and I. R. Nabi, “Fluorescence-Quenching and Resonance Energy Transfer Studies of Lipid Microdomains in Model and Biological Membranes,” Molecular Membrane Biology, Vol. 23, No. 1, 2006, pp. 5-16. doi:10.1080/09687860500473002
 L. A. Munishkina and A. L. Fink, “Fluorescence as a Method to Reveal Structures and Membrane-Interactions of Amyloidogenic Proteins,” BBA, Vol. 1768, No. 8, 2007, pp. 1862-1885. doi:10.1016/j.bbamem.2007.03.015
 C. M. Reyes, R. F. de Almeida, L. M. S. Loura and M. Prieto, “From Lipid Phases to Membrane Protein Organization: Fluorescence Methodologies in the Study of Lipid-Protein Interactions,” In: C. R. Mateo, et al., Ed., Springer Series in Biophysics, Protein-Lipid Interactions Springer-Verlag Berlin Heidelgerg, Berlin, Vol. 9, 2006.
 I. Plasencia, A. Cruz, C. Casals and J. Perez-Gil, “Superficial Disposition of the N-Terminal Region of the Surfactant Protein SP-C and the Absence of Specific SP-B-SP-C Interactions in Phospholipid Bilayers,” Biochemical Journal, Vol. 359, 2001, pp. 651-659. doi:10.1042/0264-6021:3590651
 O. Maier, V. Oberle and D. Hoekstra, “Fluorescent Lipid Probes: Some Properties and Applications (A Review),” Chemistry and Physics of Lipids, Vol. 116, No. 1-2, 2002, pp. 3-18. doi:10.1016/S0009-3084(02)00017-8
 J. Kaylor, N. Bodner, S. Edridge, G. Yamin, D. P. Hong and A. L. Fink, “Characterization of Oligomeric Intermediates in Alpha-Synuclein Fibrillation FRET Studies of Y125W/Y133F/Y136F Alpha-Synuclein,” Journal of Molecular Biology, Vol. 353, No. 2, 2005, pp. 357-372. doi:10.1016/j.jmb.2005.08.046
 A. Dusa, J. Kaylor, S. Edridge, N. Bodner, D. P. Hong and A. L. Fink, “Characterization of Oligomers during Alpha-Synuclein Aggregation Using Intrinsic Tryptophan Fluorescence,” Biochemistry, Vol. 45, No. 8, 2006, pp. 2752-2760. doi:10.1021/bi051426z
 K. L. Lim, F. L. Dawson and T. M. Dawson, “The Best of Molecular Characters in Parkinson’s Disease: Felons, Conspirators and Suspects,” Annals of the New York Academy of Sciences, Vol. 991, No. 1, 2003, pp. 80-92. doi:10.1111/j.1749-6632.2003.tb07465.x
 A. Demuro, E. Mina, R. Kayed, S. C. Milton, I. Parker and C. G. Glabe, “Calcium Dysregulation and Membrane Disrpution as Ubiquitous Neurotoxic Mechanism of Soluble Amyloid Oligomers,” The Journal of Biological Chemistry, Vol. 280, No. 17, 2005, pp. 17294-17300. doi:10.1074/jbc.M500997200
 R. Kayed, E. Head, J. L. Thompson, S. C. Milton, C. W. Cotman and C. G. Glabe, “Common Structure of Soluble Amyloid Oligomers Implies Common Mechanism of Pathogenesis,” Science, Vol. 300, No. 5618, 2003, pp. 486-489. doi:10.1126/science.1079469
 M. J. Volles and P. T. Lansbury Jr., “Zeroing in on the Pathogenic Form of Alpha-Synuclein and Its Mechanism of Neurotoxicity in Parkinson’s Disease,” Biochemistry, Vol. 42, No. 26, 2003, pp. 7871-7878. doi:10.1021/bi030086j
 K. M. Danzer, D. Haasen, A. R. Karow, S. Moussaud, M. Habeck, A. Giese, H. Kretzschmar, B. Hengerer and M. Kostka, “Different Species of Alpha-Synuclein Oligomers Induce Calcium Influx and Seeding,” The Journal of Neuroscience, Vol. 27, No. 34, 2007, pp. 9220-9232. doi:10.1523/JNEUROSCI.2617-07.2007
 M. S. Goldberg and P. T. Lansbury, “Is There a Cause- And-Effect Relationship between Alpha-Synuclein Fibrillization and Parkinson’s Disease?” Nature Cell Biology, Vol. 2, No. 7, 2000, pp. E115-E119. doi:10.1038/35041081
 H. A. Lashuel, D. Hartley, B. M. Petre, T. Walz and P. T. Lansbury, “Neurodegenerative Disease-Amyloid Pores from Pathogenic Mutations,” Nature, Vol. 418, No. 6895, 2002, pp. 291-300. doi:10.1038/418291a
 M. J. Volles and P. T. Lansbury Jr., “Vesicle Permeabilization by Protofibrillar Alpha-Synuclein Is Sensitive to Parkinson’s Disease-Linked Mutations and Occurs by a Pore-Like Mechanism,” Biochemistry, Vol. 41, No. 14, 2002, pp. 4595-4602. doi:10.1021/bi0121353
 H. A. Lashuel, B. M. Petre, J. Wall, M. Simon, R. J. Nowak, T. Walz and P. T. Lansbury Jr., “Alpha-Synuclein, Especially the Parkinson’s Disease-Associated Mutants Forms Pore-Like Annular and Tubular Protofibrils,” Journal of Molecular Biology, Vol. 322, No. 5, 2002, pp. 1089-1102. doi:10.1016/S0022-2836(02)00735-0
 L. Maroteaux, J. T. Campanelli and R. H. Scheller, “Synuclein: A Neuron Specific Protein Localized to the Nucleus and Presynaptic Nerve Terminal,” The Journal of Neuroscience, Vol. 8, No. 8, 1988, pp. 2804-2815.
 P. H. Weinreb, W. Zhen, A. W. Poon, K. A. Conway and P. T. Lansbury Jr., “NACP a Protein Implicated in Alzheimer’s Disease and Learning Is Natively Unfolded,” Biochemistry, Vol. 35, No. 43, 1996, pp. 13709-13715. doi:10.1021/bi961799n
 R. Bussell, T. F. Ramlall and D. Eliezer, “Helix Periodicity, Topology and Dynamics of Membrane-Associated Alpha-Synuclein,” Protein Science, Vol. 14, No. 4, 2005, pp. 862-872. doi:10.1110/ps.041255905
 W. S. Davidson, A. Jonas, D. F. Clayton and J. M. George, “Stabilization of Alpha-Synuclein Secondary Structure upon Binding to Synthetic Membranes,” The Journal of Biological Chemistry, Vol. 273, No. 16, 1998, pp. 9443-9449. doi:10.1074/jbc.273.16.9443
 K. A. Conway, J. D. Harper and P. T. Lansbury Jr., “Fibrils Formed in Vitro from Alpha-Synuclein and Two Mutants Forms Linked to Parkinsons’s Disease Are Typical Amyloid,” Biochemistry, Vol. 39, No. 10, 2000, pp. 2552-2563.
 M. Zhu, J. Li and A. L. Fink, “The Association of α-Synuclein with Membranes Affects Bilayer Structure, Stability and Fibril Formation,” The Journal of Biological Chemistry, Vol. 278, No. 41, 2003, pp. 40186-40197. doi:10.1074/jbc.M305326200
 S. Chandra, X. Chen, J. Rizo, R. Jahn and T. C. Sudhof, “A Broken Alpha A Broken Alpha-Helix in Folded Alpha-Synuclein,” The Journal of Biological Chemistry, Vol. 278, No. 17, 2003, pp. 15313-15318. doi:10.1074/jbc.M213128200
 V. N. Uversky, J. Li and A. L. Fink, “Evidence for a Partially Folded Intermediate in Alpha-Synuclein Fibril Formation,” The Journal of Biological Chemistry, Vol. 276, No. 14, 2001, pp. 10737-10744.
 J. C. Lee, R. Langen, P. A. Hummel, H. B. Gray and J. R. Winkler, “Alpha-Synuclein Structures from Fluorescence Energy-Transfer Kinetics: Implications for the Role of the Protein in Parkinson’s Disease,” Proceedings of the National Academy of Sciences of the United States of America, Vol. 101, No. 47, 2004, pp. 16466-16471. doi:10.1073/pnas.0407307101
 K. Furukawa, et al., “Plasma Membrane Ion Permeability Induced by Mutant α-Synuclein Contributes to the Degeneration of Neural Cells,” Journal of Neurochemistry, Vol. 97, No. 4, 2006, pp. 1071-1077. doi:10.1111/j.1471-4159.2006.03803.x
 B. D. van Rooijen, M. M. A. E. Claessens and V. Subramaniam, “Membrane Binding of Oligomeric Alpha-Synuclein Depends on Bilayer Charge and Packing,” FEBS Letters, Vol. 582, No. 27, 2008, pp. 3788-3792. doi:10.1016/j.febslet.2008.10.009
 M. Stockl, P. Fischer, E. Wanker and A. Hermann, “Alpha Synuclein Selectively Binds to Anionic Phospholipids Embedded in Liquid-Disordered Domains,” Journal of Molecular Biology, Vol. 375, No. 5, 2008, pp. 1394-1404. doi:10.1016/j.jmb.2007.11.051
 B. D. van Rooijen, M. M. A. E. Claessens and V. Subramaniam, “Lipid Bilayer Disruption by Oligomeric Alpha-Synuclein Depends on Bilayer Charge and Accessibility of the Hydrophobic Core,” Biochim Biophys Acta Biomembr, Vol. 1788, No. 6, 2009, pp. 1271-1278. doi:10.1016/j.bbamem.2009.03.010
 M. St?ckl, M. M. Claessens and V. Subramaniam, “Kinetic Measurements Give New Inshights into Lipid Membrane Permeabilization by Alpha-Synuclein Oligomers,” Molecular BioSystems, Vol. 8, No. 1, 2012, pp. 338-345. doi:10.1039/c1mb05293d
 J. E. Shaw, R. F. Epand, R. M. Epand, Z. Li, R. Bittman and C. M. Yip, “Correlated Fluorescence-Atomic Force Microscopy of Membrane Domains: Structure of Fluorescence Probes Determines Lipid Localization,” Biophysical Journal, Vol. 90, No. 6, 2006, pp. 2170-2178. doi:10.1529/biophysj.105.073510
 M. Stockl, P. Fischer, E. Wanker and A. Herrmann, “α-Synuclein Selectively Binds to Anionic Phospholipids Embedded in Liquid-Disordered Domains,” Journal of Molecular Biology, Vol. 375, No. 5, 2008, pp. 1394-1404. doi:10.1016/j.jmb.2007.11.051
 B. D. van Rooijen, M. M. A. E. Claessens and V. Subramaniam, “Membrane Permeabilization by Oligomeric α-Synuclein: In Search of the Mechanism,” Plos One, Vol. 5, No. 12, 2010, Article ID: e14292. doi:10.1371/journal.pone.0014292