Figure 3
Transient dimer formation of SNAP-D2L receptors.
(a) 48 sequential frames of two Alexa546-labeled SNAP-D2L receptors showing transient dimer formation (frame rate of 19.32 fps) (also shown in Supplementary Movie S3). (b) Intensity profile (blue) of the marked fluorescent SNAP-D2L receptor shown in (a), compared to background intensity (grey). (c) A histogram of the lifetimes of 120 SNAP-D2L receptor dimers taken from trajectories similar to those in (a) and collected in 0.5 s bins. The solid line represents a one-phase exponential fit for a mean lifetime of 0.50 s (95% confidence interval: 0.44–0.60). (d) Effect of the size of SNAP-D2L receptors on their lateral diffusion. The diffusion coefficients (Dlat) of the analyzed receptor particles (n) are shown (monomers −0.104 ± 0.052 μm2 s−1, n = 412 from 3 cells and dimers −0.075 ± 0.027 μm2 s−1, n = 373 from 3 cells. Data represent mean ± s.d. The difference, determined by an unpaired t-test (****p-value < 0.0001) is significant and shows that the receptor mobility is negatively correlated with the size of the receptor complexes.
