OS mobility shows low affinity binding of prenylated probes to disc membranes and that binding affinity of myristoylated probes scales with charge. (A) Representative time course images of FRAPa or FRAPb experiments. Pre-blast images: Distributions before two-photon photoactivation or photobleaching. Scale bars, 10 µm. (B) Time courses of fluorescence relaxation at the center of the photoconversion sites fitted with a 3D cylindrical diffusion model, magenta lines. Black lines: Data-model difference. (C) Root-mean-square (RMS) errors plotted against D. red circle indicates D with lowest error, and value shown above plots. (D) Bar chart of average DOSs. Error bars are SEM. ANOVA followed by two-tailed, homoscedastic t test with Tukey correction showed that DOSs for all lipidated probes were significantly different from the DOS for PAGFP. DOSs among 0Far and GRK1 were not different. Significance tables: P ≤ 0.05; NS, not significant. n for each construct: 0Far, 6; GRK1, 5; PAGFP, 6; Myr-8, 8; Myr0, 3; and Myr+8, 3.
