FIGURE 4:

Turnover of α-actinin in the cortex. (A) Consecutive confocal images of a FRAP experiment in a region comprising the actin cortex for a cell expressing GFP–α-actinin. Circles of different colors indicate the same regions as in Figure 2. Scale bar, 1 μm. (B) Fluorescence recovery averaged over 20 cells. Error bars, SDs. Red line, fit of a sum of two exponentials to the data. (C) Logarithmic acceleration plots for full-length α-actinin and for its actin-binding domain (solid line). Two distinct subpopulations participate in the turnover of the full-length protein, whereas only a single population participates in the turnover of the actin-binding domain.