FRAP fluorescence recovery after

FRAP (fluorescence recovery after photo bleaching) analysis was originally developed in the mid-1970s to study the diffusion of biomolecules in living cells (Edidin et al, 1976). Flowever, due to the increased availability of GFP tags and advances in the bleaching capabilities of confocal microscopes, this... 

CPK creatine phosphokinase FRAP fluorescence recovery after photolysis... 

Looks at the role of caveolins in the formation of membrane caveolae Covers the investigation of hop diffusion of membrane lipids using FRAP (fluorescence recovery after photobleaching)... 

AR Androgen receptor ER Estrogen receptor FLIP Fluorescence loss in photobleaching FRAP Fluorescence recovery after photobleaching FRET Fluorescence resonance energy transfer GR Glucocorticoid receptor NER Nucleotide excision repair UV Ultra-violet... 

The FRAP (fluorescence recovery after photobleaching) technique uses photobleaching to measure molecular diffusion and can be used if the material in question is confined to a specific plane (e.g., a membrane or cytoskeletal filaments adsorbed on a surface). The fluorophores... 

One of the most popular applications of molecular rotors is the quantitative determination of solvent viscosity (for some examples, see references [18, 23-27] and Sect. 5). Viscosity refers to a bulk property, but molecular rotors change their behavior under the influence of the solvent on the molecular scale. Most commonly, the diffusivity of a fluorophore is related to bulk viscosity through the Debye-Stokes-Einstein relationship where the diffusion constant D is inversely proportional to bulk viscosity rj. Established techniques such as fluorescent recovery after photobleaching (FRAP) and fluorescence anisotropy build on the diffusivity of a fluorophore. However, the relationship between diffusivity on a molecular scale and bulk viscosity is always an approximation, because it does not consider molecular-scale effects such as size differences between fluorophore and solvent, electrostatic interactions, hydrogen bond formation, or a possible anisotropy of the environment. Nonetheless, approaches exist to resolve this conflict between bulk viscosity and apparent microviscosity at the molecular scale. Forster and Hoffmann examined some triphenylamine dyes with TICT characteristics. These dyes are characterized by radiationless relaxation from the TICT state. Forster and Hoffmann found a power-law relationship between quantum yield and solvent viscosity both analytically and experimentally [28]. For a quantitative derivation of the power-law relationship, Forster and Hoffmann define the solvent s microfriction k by applying the Debye-Stokes-Einstein diffusion model (2)... 

Total internal reflection fluorescence (TIRF) microscopy, fluorescence in situ hybridization (FISH), fluorescence recovery after photobleaching (FRAP), fluorescence lifetime imaging microscopy (FLIM). 

To increase the speed of the TIRF-based kinetic techniques, the perturbation can be optical rather than chemical. If the evanescent wave intensity is briefly flashed brightly, then some of the fluorophores associated with the surface will be photobleached. Subsequent exchange with unbleached dissolved fluorophores in equilibrium with the surface will lead to a recovery of fluorescence, excited by a continuous but much attenuated evanescent wave. The time course of this recovery is a measure of the desorption kinetic rate k2. This technique1-115) is called TIR/FRAP (or TIR/FPR) in reference to fluorescence recovery after photobleaching (or fluorescence photobleaching recovery). 

Lateral diffusion of phospholipids in model membranes at ambient pressure has been studied over the years by a variety of techniques including fluorescence recovery after photobleaching (FRAP), spin-label ESR, pulse field gradient NMR (PFG-NMR), quasielastic neutron scattering (QENS), excimer fluorescence and others.In general, the values reported for the lateral diffusion coefficient (D) range from 10 to 10 cm /s in the... 

Fig. 2. Exchange of histones Hl.l and H2B from chromatin in interphase cells by analysis with fluorescence recovery after photobleaching (FRAP). Half of a nucleus of an SK-N cell expressing GFP-Hl.l was bleached (upper panel), and the recovery monitored over the times shown. Similarly, a region of a nucleus of an SK-N cell stably expressing H2B-CFP was bleached (lower panel), and the recovery monitored over the times shown. Whereas unbleached HI molecules move into the bleached region after a few minutes, the H2B histones are much less mobile, since the bleached region shows no recovery (from Ref [23]). Scale bar 5 pm.

Fig. 7. GFP-GR bound to the MMTV array was analyzed by fluorescence recovery after photobleaching (FRAP). The bleached region is indicated in the image of the pre-bleached nucleus (A). The pre-bleach array is shown in (B), the post-bleach image (C), and at 4.1 s (D) and 11.6 s (E) post-bleach. This analysis, along with Fluorescence Loss in Photobleaching (FLIP) experiments, show that GFP-GR undergoes rapid exchange with the array (from Ref. [58]). Scale bar 5 pm.

The velocity of interstitial fluid in solid tumors is often lower than the resolution of experimental techniques, which is 0. lpm/sec, except in some special tumor models. For example, Chary and Jain (1989) have examined interstitial fluid velocity in granulation tissues and VX2 mammary carcinoma grown in rabbit ear chambers, using the fluorescence recovery after photobleaching (FRAP) technique. The average velocities in both tissues are about 0.6 pm/sec. 

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