title: Fluorescence lifetime dynamics of enhanced green fluorescent protein in protein aggregates with expanded polyglutamine.
abstract: Protein aggregation is one of the characteristic steps in a number of neurodegenerative diseases eventually leading to neuronal death and thorough study of aggregation is required for the development of effective therapy. We apply fluorescence lifetime imaging for the characterization of the fluorescence dynamics of the enhanced green fluorescent protein (eGFP) in fusion with the polyQ-expanded polyglutamine stretch. At the expansion of polyQ above 39 residues, it has an inherent propensity to form amyloid-like fibrils and aggregates, and is responsible for Huntington's disease. The results of the experiments show that expression of the eGFP in fusion with the 97Q protein leads to the decrease of the eGFP fluorescence lifetime by approximately 300 ps. This phenomenon does not appear in Hsp104-deficient cells, where the aggregation in polyQ is prevented. We demonstrate that the lifetime decrease observed is related to the aggregation per se and discuss the possible role of refractive index and homo-FRET in these dynamics.
authors.affiliation: National Yang-Ming University, Institute of Biophotonics, Taipei, Taiwan.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Ghukasyan
authors.forename: Chih-Chun
authors.initials: CC
authors.lastname: Hsu
authors.forename: Chia-Rung
authors.initials: CR
authors.lastname: Liu
authors.forename: Fu-Jen
authors.initials: FJ
authors.lastname: Kao
authors.forename: Tzu-Hao
authors.initials: TH
authors.lastname: Cheng
mesh_terms: D000704:Analysis of Variance; D016880:Anisotropy; D048708:Cell Growth Processes / Q000502:physiology; D003116:Color; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D049452:Green Fluorescent Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012031:Refractometry
chemical_list: D046912:Multiprotein Complexes; D010455:Peptides; D011506:Proteins; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; C097188:polyglutamine