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Fig. 4
Subfunctionalization of Cxcl12 affects the affinity towards and activation of Cxcr4. (A) The concentration of free ligand is compared with the concentration of ligand (green) on Cxcr4b-containing membranes (red). (B) Median apparent KD values of dual-color FCS measurements. Error bars depict 95% confidence intervals and n is the number of measurements performed. Horizontal bars identify significant pairwise differences; P<0.05 (Kolmogorov-Smirnov test). (C) Internalization of Cxcr4b as a measure of Cxcl12 activity in vitro. Mean percentage of HEK293T cells expressing Cxcr4-YPet showing receptor internalization following incubation with recombinant Cxcl12 or with control ligand-free medium (see Fig. S2 in the supplementary material for representative results). Error bars represent s.e.m. Three experiments with 100 cells each were performed. Significant pairwise differences are identified by horizontal bars; P<0.05 (one-way ANOVA).