FLNA deficiency enhances tonic and CXCL12-induced internalization of WHIM-like CXCR4 receptors. (A) Dot plots of unstimulated A7 and M2 cells stably expressing GFP-tagged X4^WT and X4^WHIM stained with anti-CXCR4 antibody. (B) Basal cell surface levels of X4^WHIM and X4^WHIM-ICL3ΔCt in A7 (solid bars) and M2 cells (open bars) determined by anti-CXCR4 staining. The ratio is shown (×100) between the percentage of anti-CXCR4–stained and GFP⁺ cells for each construct (n = 3). *P < .05, 2-tailed Student t test. (C) Kinetics of CXCL12-induced X4^WHIM and X4^WHIM-ICL3ΔCt receptor internalization in A7 (solid symbols) and M2 cells (open symbols). In all cases, data are mean ± SEM of a representative experiment (n = 3). *P < .05; ***P < .001, 2-way ANOVA with Bonferroni posttest.