Fig. 5: Dual-color real-time SFSRM imaging reveals the microtubule-vesicle interactions.
From: Single-frame deep-learning super-resolution microscopy for intracellular dynamics imaging
a Representative dual-channel image of microtubules (green) and vesicles (magenta) in Beas2B cells after Epidermal Growth Factor (EGF) protein endocytosis. b Examples of vesicle transport dynamics. First row: moving back and forth along a microtubule; Second row: moving around a microtubule along a sinusoidal-like trajectory; Third row: colliding with another vesicle. c Comparison of the dual-color LR and SR images. The trajectory in SR image shows the motions of vesicle along microtubule at millisecond scale. d Comparison of trajectories recorded at 2 Hz and 100 Hz. e Mean-squared displacement (MSD) analysis of trajectories in d. MSD reflects the mean-squared-distance (∆r2 (τ)) of the vesicle traveled in a certain lag time τ, which typically follows the power-law trend 〈∆r2 (τ) 〉∝τα. α indicates the characteristic of the motion. A smaller α indicates a more random or diffusive motion while a larger α indicates a more directed motion. f Statistical comparison of vesicle instantaneous velocity recorded at 2 Hz and 100 Hz. g Examples of microtubule dynamics resulting in nondirected transport of vesicles. First row: an example showing transverse movements of a microtubule deliver the vesicle to a nearby microtubule. Second row: example showing random fluctuations of surrounding microtubules facilitate the vesicle to switch to different microtubules. h The statistical comparison of the instantaneous velocity of the directed/nondirected transport and their representative trajectories. An image sequence containing 800 frames of images was used to analyze the instantaneous velocity. i Vesicle transport dynamics at different types of microtubule intersections. j The statistical comparison of the dwell time at different types of intersections and their percentages in cells (pie chart). 43 intersections were analyzed. Boxplots are drawn from the 25th to 75th percentile with the horizontal bar at the median and the whiskers extending to the minima and maxima. Scale bar, 2 µm (a); 200 nm (b); 1 µm (c); 500 nm (g, i).
