Fig. 4Analysis of TfR-GFP dynamics in living cells. (a) Schematic representation of a GFP-tagged TfR diffusing
within the cytoskeleton meshwork, with particular emphasis on the F-actin mesh close to the plasmamem-
brane. (b) TIRF microscopy image of a cell expressing GFP-tagged TfR (left) and the detail of the ROI on the
membrane selected for imaging (right). (c) Temporal evolution of the correlation function with the
corresponding Gaussian fit and residues. (d) The autocorrelation plot shows that the characteristic time of
the fluctuations is shorter than the total length of the measurement (arrow). Thus, immobile fraction removal is
a safe operation. (e)iMSD vs time plot for GFP-TfR in physiological conditions (red curve) and after 30 min of
Fluctuation-Based Diffusion Laws 285