Ca²⁺ mobilization and F-actin polymerization in response to CXCL11 in HEK 293 cells expressing WT and the S245A CXCR3. (A) Intracellular Ca²⁺ mobilization mediated by CXCR3 in HEK 293-CXCR3 cells. Fluorescence changes in HEK 293 cells expressing WT and S245A CXCR3 loaded with 10 mM Fura-3 were measured upon stimulation with 1 mg/mL CXCL11 as indicated by arrows and described in “Materials and methods.” (B) F-actin polymerization in HEK 293 cells expressing WT and S245A CXCR3 in response to 1 mg/mL CXCL11 at various time points. F-actin polymerization was monitored by FACS as described in “Materials and methods.”