(a) Fluorescence recovery after photobleaching (FRAP) of
EGFR-mCitrine expressed in HeLa cells at different temperatures during the
cryo-arrest protocol. Shown are fluorescence recovery curves obtained at
37°C (n=11 cells), 4°C (n=19) and -45°C (n=19) after
bleaching a 2 μm spot on the plasma membrane. (b) FRAP of
cytoplasmic eGFP expressed in HeLa cells at -45°C. Shown are the
fluorescence recovery curves measured in concentric areas within the bleached
spot (an innermost circle with a diameter of 0.5 μm, an intermediate
circle with 1 μm and the full bleached area with a diameter of 2
μm; n=20 cells. (c, d) Single molecule tracking of
Cy3-SNAP-EGFR in HeLa cells measured at 37°C (n=10 cells), 4°C
(n=14) and -45°C (n=14). (c) Mean squared displacement (MSD)
of the confined fractions of Cy3-SNAP-EGFR. Numbers represent the percentage of
molecules that are included in this confined fraction. (d)
Fractions of detected molecule tracks that are classified as confined and
mobile. (a, b) mean ± s.d., (c,
d) mean ± s.e.m. All data was obtained from 3
independent experiments.