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. 2018 Aug 6;217(8):2831–2849. doi: 10.1083/jcb.201711104

Table 1. Individual GPCR and cilia parameters: low frame rate (3–5 fps) tracking.

Ciliuma Tracking time Cilium length GPCR densityb GPCRs on ciliumc Amd Daxe Dmf MIg fcsh MSDinti
min μm μm−2 % μm2/s μm2/s μm2
R1 10.5 3.7 269.2 932 0.24 0.074 0.148 0.77 1.0 0.079
R2 3.0 4.2 1,487.5 5,833 1.34 0.026 0.051 0.35 0.7 0.020
R3 4.0 1.9 4,965.2 8,735 4.47 0.035 0.069 0.78 1.0 0.020
R4 17.1 3.7 2,790.7 9,721 2.51 0.135 0.270 0.50 1.0 0.079
R5 (1) 12.0 2.9 1,653.2 4,592 1.49 0.015 0.030 0.61 1.0 0.009
R5 (2) 12.0 0.081 0.163 0.34 1.0 0.049
R6 8.4 3.8 1,607.6 5,795 1.45 0.030 0.059 0.42 0.9 0.018
R7 4.5 4.3 30.5 123 0.03 0.145 0.290 0.26 1.0 0.070
R8 9.7 2.4 873.2 1,969 0.79 0.095 0.189 0.70 1.0 0.056
Mean R 3.6 1,744.9 4,713 1.54 0.071 0.141 0.53 0.96 0.045
SEM R 0.3 512.5 1,172 0.47 0.016 0.032 0.07 0.03 0.009
S1 11.9 5.6 557.5 2,947 0.50 0.085 0.170 0.39 1.0 0.027
S2 (1) 12.7 4.8 10,676.0 48,368 9.61 0.167 0.334 0.62 1.0 0.099
S2 (2) 12.7 0.180 0.361 0.55 1.0 0.099
S3 (1) 9.2 7.4 6,534.6 45,267 5.88 0.063 0.126 0.63 1.0 0.037
S3 (2) 9.2 0.032 0.065 0.62 1.0 0.020
S4 28.3 7.0 7,292.1 47,937 6.56 0.079 0.157 0.21 0.7 0.047
S5 14.7 8.1 1,591.5 12,077 1.43 0.141 0.282 0.28 1.0 0.079
S6 7.5 10.0 1,761.3 16,631 1.59 0.075 0.149 0.50 0.8 0.064
S7 14.8 4.7 2,591.2 11,404 2.33 0.109 0.217 0.44 1.0 0.075
S8 4.1 8.2 2,612.2 20,191 2.35 0.121 0.242 0.39 0.9 0.096
S9 5.2 6.4 1,461.0 8,748 1.31 0.086 0.172 0.19 0.3 0.010
S10 6.3 7.2 2,412.5 16,257 2.17 0.138 0.276 0.49 1.0 0.099
S11 (1) 16.0 7.3 1,487.1 10,205 1.34 0.129 0.258 0.46 1.0 0.056
S11 (2) 16.0 0.111 0.222 0.56 1.0 0.056
Mean S 7.2 3,543.4 21,821 3.19 0.108 0.216 0.45 0.91 0.062
SEM S 0.5 1,061.4 5,640 0.86 0.011 0.022 0.04 0.05 0.008
a

Individual cilia: R, Rhoi3S; S, SSTR3. Numbers in parentheses identify individual Qdot-GPCR for cilia in which more than one was labeled.

b

GPCR density was estimated by calibration of the optical system with recombinant EGFP of known concentrations. Confinement of the EGFP label to the ciliary membrane and the sampling by the optical system were accounted for as described previously (Peet et al., 2004).

c

Total number of GPCRs within the given cilium.

d

Membrane area fraction occupied by the expressed GPCRs.

e

Dax is the 1D axial diffusion coefficient estimated from the initial slope of the MSD(τ) plot for an individual Qdot-GPCR.

f

Effective membrane diffusion coefficient: Dm ≈ 2Dax. Dax underestimates the true 2D membrane diffusion coefficient approximately twofold. Note the similarity of the mean microscopic Rhoi3S diffusion coefficient in ciliary membranes, Dm, reported here to the mean macroscopic lateral diffusion coefficient estimated for rhodopsin within discrete lobules of photoreceptor disc membranes, Dlat = 0.130 ± 0.012 µm2/s (Najafi et al., 2012a).

g

Mobility index (see text).

h

Fraction of cilium length sampled by the indicated GPCR.

i

MSD value at the y-intercept of the linear regression of the first two MSD(τ) points.