title: Millisecond spatiotemporal dynamics of FRET biosensors by the pair correlation function and the phasor approach to FLIM.
abstract: Here we present a fluctuation-based approach to biosensor Förster resonance energy transfer (FRET) detection that can measure the molecular flow and signaling activity of proteins in live cells. By simultaneous use of the phasor approach to fluorescence lifetime imaging microscopy (FLIM) and cross-pair correlation function (pCF) analysis along a line scanned in milliseconds, we detect the spatial localization of Rho GTPase activity (biosensor FRET signal) as well as the diffusive route adopted by this active population. In particular we find, for Rac1 and RhoA, distinct gradients of activation (FLIM-FRET) and a molecular flow pattern (pCF analysis) that explains the observed polarized GTPase activity. This multiplexed approach to biosensor FRET detection serves as a unique tool for dissection of the mechanism(s) by which key signaling proteins are spatially and temporally coordinated.
authors.affiliation: Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92617, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Hinde
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Digman
authors.forename: Klaus M
authors.initials: KM
authors.lastname: Hahn
authors.forename: Enrico
authors.initials: E
authors.lastname: Gratton
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods*; D041681:NIH 3T3 Cells; D011506:Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D013997:Time Factors; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D011506:Proteins; D020830:rac1 GTP-Binding Protein; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein