Fig. 3
From: Single molecule dynamics in a virtual cell combining a 3-dimensional matrix model with random walks
Single molecules diffusing within a tubular network. (A) Model: “virtual cell” with an interconnected tubular network (tube diameter = 0.2 µm). Green dots are molecules embedded in the tubular membranes; Red dots are molecules diffusing within the luminal space of the network. Experimental Data: (B) SD-projection image showing GFP-tagged nicotinic receptors retained in the ER of the HEK293 cell. (C) SD-projection image of KIR3.1-GFP potassium ion channels in the ER of a CHO cell. Scale bar 2 µm. (D) Model: Simulated SD-projection image showing fluorescent molecules diffusing (D = 0.2 µm2⋅s−1) in the tubular membranes (green, left side) and fluorescent molecules (D = 2 µm2⋅s−1) moving within the tube lumen (red, right side) Scale bar 2 µm (see Movie 6). (E) MSD vs dT plots produced by tracking the paths of 667 individual fluorophores for experimental data (nicotinic receptors, shown in panel (B) (red line), and 963 simulated membrane-localised molecules (green line, shown on left in panel (D). (F) Distribution of diffusion constants, measured from the initial gradient of MSD v dT plots of individual molecules; nicotinic receptors in HEK293 cell (red line); virtual cell (green line). Note: same data set as E.
