Figure 2.

Methods for measurement of fluorescence intensities on single cells. (a, b) Line intensity profile across the perinuclear region of the cell to determine the peak intensity (I _peak) within the cell cytoplasm. (c, d) Fluorescence intensity histogram over the cell cross-section. The average intensity in the cell (I _avg) is determined by dividing the total intensity (I _total) by the total number of pixels within the cell contour (n) and subtracting the background intensity (I _B), while the normalized intensity of the perinuclear compartment (I _N,pc) is calculated according to the expression on the right