Fig. 1
From: Raftophilic rhodopsin-clusters offer stochastic platforms for G protein signalling in retinal discs
Single-molecule tracking of rhodopsin in rod outer segment (ROS) disc membranes. a Left: Intact ROSs associated with rod inner segments. Middle: mechanically fragmented ROSs (f-ROSs). Right: Disc membrane exposed at the bottom of an f-ROS. b Schematic diagram for probing rhodopsin (Rh) in the disc membrane. c Visualization of single fluorescent spots on the disc membrane, at the bottom of an f-ROS, standing on a glass surface placed on a total internal reflection fluorescence microscope (TIRFM) equipped with electron-multiplying-charge coupled device (EM-CCD) camera. d Snapshot of a disc incubated with 0.2 nM fluorescent Fab′-1D4. e Representative trajectories of rhodopsin on a dark-adapted disc under physiological conditions. Individual trajectories are colour-coded. Scale bars for both (d) and (e): 2 μm. f Histogram of D100 ms calculated from 432 trajectories of rhodopsin. g Optimal three-state HMM of rhodopsin inferred by vbSPT. Diffusion coefficients (D1−3), dwell times (τ1−3), and relative occupancies of three states (S1, S2 and S3) and the transition rates between them are indicated. Circle sizes reflect relative occupancy. h A subset of 100 trajectories is colour-coded according to diffusive state. Square-region is enlarged. i Diffusion coefficients (Dstate) and occupancies of three diffusive states in an optimal HMM of dark-state rhodopsin are indicated in D100 ms-histogram (grey bars) (navy bar: state-1, blue bar: state-2, magenta bar: state-3). Coloured numbers are Dstate. Grey arrowhead indicates the median value of D100 ms
