Figure 4.

Arrestin is not required for chemokine degradation by ACKR3. A, Western blotting of lysates transfected with siRNA targeting β-arrestin1, β-arrestin2, or both arrestin isoforms, using pan-arrestin antibody. B and C, degradation of ¹²⁵I-CXCL12 (B) or ¹²⁵I-CXCL11 (C) is unaffected by arrestin knockdown with siRNA. D and E, MEFs from wildtype (D) or β-arr1^−/−/β-arr2^−/− double knock-out (E) animals were transduced with lentivirus coding for GFP (control) or hACKR3, as indicated. Degradation of ¹²⁵I-CXCL12 (red symbols) or ¹²⁵I-CXCL11 (blue symbols) was determined; stacks show undegraded chemokine (top, white fields), degraded chemokine debris (middle, colored fields), and cell-associated chemokine (bottom, black fields). Degradation was blocked using 200 nm of unlabeled chemokine or 1 μm AMD3100, as indicated. A, one representative experiment of three independent experiments; B–E, pooled data of three independent experiments conducted in duplicate. Error bars, S.D.