Fig. 4: Ultrahigh sensitivity in imaging microtubules in live cells.
a Exemplary raw C-iSCAT image of the periphery of a COS-7 cell showing vesicles, ER network and MT. Corresponding CF images of MTs labeled with mEGFP-tubulin (b) and ER tubules labeled with CytERM-mScarlet (c). Scale bars are 1 μm. d Overlay of a–c for a region marked in a. Scale bar is 1 μm. e A cross section along the cut in d, displaying the C-iSCAT (black) and fluorescence signals of MT (cyan) and ER (magenta). The focal plane was adjusted to be able to extract the maximum negative contrast of both MTs and ER tubules. f Exemplary raw C-iSCAT image from the periphery of a COS-7 cell at t = t0 and t = t0 + 20s. The white arrows indicate the configuration of two visible MTs in between the ER tubular network. ER tubules undergo motor-dependent “sliding” along the length of the MTs. Scale bar is 2 μm. g Optical flow map depicting ER sliding and dynamics of ER nanodomains. Direction and length of the green arrows indicate the direction and amplitude of motion of the ER network. h Time course over 8 s shows the position of the previously identified MT and a vesicle being transported along it. Symbols mark the consecutive locations of the vesicle. Scale bar 1 μm.
