Figure 4.

Effects of CXC mutants on another chemokine receptor, ACKR3. A, displacement of [¹²⁵I]CXCL12-WT from ACKR3 was measured for each construct via scintillation after a 4- h equilibration with membrane suspensions at room temperature. Measurements were performed in duplicate from at least three independent experiments. B, recruitment of β-arrestin was measured via the Tango assay performed in quadruplicate from at least three independent experiments. C, summary of the X-factor impact in each signaling and binding experiment. CXCL12-P10del requires a significantly higher concentration to reach 50% effectiveness. CXCL12-P10Q is intermediate between WT and P10del.