Figure 2

FCS analysis of living cells in culture.

(a) Upper panel: Confocal microscopy (phase contrast image) showing measurement points in the extracellular (1 and 2) and intracellular (3–6) spaces of HeLa S3 cells in culture. 1, culture medium away from plasma membrane; 2, interphase between the extracellular space and plasma membrane; 3, plasma membrane; 4, cytoplasm; 5, nuclear membrane; 6, nucleoplasm. Lower panel: ADC values of the extracellular and intracellular spaces of living cells in culture. ADC values of the Dio molecules are plotted for 6 measurement points. *^, ** Significantly different from the values in the extracellular space (*p < 0.001, **p < 0.05; Tukey-Kramer test). (b) Graph showing the FCS autocorrelation curves of Dio molecules in living cells in culture. Each curve was averaged from one location in each of the 6 cellular compartments in a single living cell. Note that, for example, curve 1 (extracellular space) shifts to the right compared with curve 2 (interface between the extracellular space and plasma membrane), indicating that curve 1 has a higher ADC value than curve 2.