Parameter estimates from PAF [photoactivation of fluorescence] and FRAP [fluorescence recovery after photobleaching] in BAECs [bovine aortic endothelial cells]

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Organism Cow Bos Taurus
Reference McGrath, J.L., Y. Tardy, C.F. Dewey Jr, J.J. Meister, J.H. Hartwig. 1998. Simultaneous measurements of actin filament turnover, filament fraction, and monomer diffusion in endothelial cells. Biophys. J. 75:2070–2078. DOI: 10.1016/S0006-3495(98)77649-0 p.2076 table 1PubMed ID9746549
Method Abstract: "The analogous techniques of photoactivation of fluorescence (PAF) and fluorescence recovery after photobleaching (FRAP) have been applied previously to the study of actin dynamics in living cells. Traditionally, separate experiments estimate the mobility of actin monomer or the lifetime of actin filaments. A mathematical description of the dynamics of the actin cytoskeleton, however, predicts that the evolution of fluorescence in PAF and FRAP experiments depends simultaneously on the diffusion coefficient of actin monomer, D, the fraction of actin in filaments, FF, and the lifetime of actin filaments, tau (, Biophys. J. 69:1674-1682). Here [investigators] report the application of this mathematical model to the interpretation of PAF and FRAP experiments in subconfluent bovine aortic endothelial cells (BAECs)."
Comments P.2073 right column 2nd paragraph: "Estimates of D (diffusion coefficient of actin monomer), FF (fraction of actin in filamentous form), and τ (turnover time (characteristic lifetime) of actin filaments) by the Tardy model: The evolution of fluorescence in PAF and FRAP experiments was biphasic, indicating the presence of two dynamically distinct populations of actin. Corrected PAF and FRAP data are shown in Fig. 4, a and b, respectively. Each corrected experiment was fit to the Tardy model to determine D, FF, and τ. All correlation coefficients exceeded 0.91. The parameters for PAF are: D = 3.1 ± 0.4 × 10^−8 cm^2/s (n = 20), FF = 0.36 ± 0.04 (n = 19), τ = 7.5 ± 2.0 min (n = 17) those for FRAP are: D = 5.8 ± 1.2 10^−8 cm^2/s (n = 25), FF = 0.50 ± 0.04 (n = 26), and τ = 4.8 ± 1.0 min (n = 26). The differences in the PAF and FRAP estimates of D, FF, and τ are statistically significant (pD < 0.0005, pFF < 0.0005, pτ < 0.025) (Table 1). For each study a simulated experiment was generated with the Tardy model and average parameter values. These simulations are plotted along with the data in Fig. 4 to demonstrate the quality of the model fit." CRIA=Caged-resorufin iodacetamide actin. CFSA=5- (and 6) carboxyfluorescein succinimidyl esterlabeled actin
Entered by Uri M
ID 112785