TABLE 3.
Effects of arginine swap mutations on ligand pharmacology at rat GPR35
Data are rat GPR35 pEC50 values and ΔpEC50 compared with wild type. All studies employed the BRET-based GPR35–β-arrestin 2 interaction assay. Potency estimates of <4 reflect lack of adequate data fit.
| Ligand | Wild-Type | Ser161Arg |
Arg4.60Met |
Arg4.62Leu |
Gln6.58Arg |
Ser7.32Arg |
Glu6.58Arg, Ser7.32Arg |
||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| pEC50 | ΔpEC50 | pEC50 | ΔpEC50 | pEC50 | ΔpEC50 | pEC50 | ΔpEC50 | pEC50 | ΔpEC50 | pEC50 | ΔpEC50 | ||
| Zaprinast | 7.01 ± 0.02 | 6.07 ± 0.02*** | −0.94 | 5.03 ± 0.08*** | −1.98 | 5.96 ± 0.04*** | −1.05 | 6.97 ± 0.08 | −0.04 | 7.03 ± 0.06 | +0.02 | 6.77 ± 0.2 | −0.24 |
| Lodoxamide | 7.90 ± 0.02 | 7.47 ± 0.002** | −0.43 | 5.18 ± 0.13*** | −2.72 | 6.24 ± 0.07*** | −1.66 | 8.09 ± 0.08 | +0.19 | 8.25 ± 0.08** | +0.35 | 8.15 ± 0.2* | +0.25 |
| Bufrolin | 8.00 ± 0.02 | 8.08 ± 0.007 | +0.08 | 7.25 ± 0.26* | −0.75 | 7.11 ± 0.06** | −0.89 | 8.16 ± 0.1 | +0.16 | 8.1 ± 0.1 | +0.1 | 7.88 ± 0.28 | −0.12 |
| Cromolyn | 5.42 ± 0.03 | 4.32 ± 0.12*** | −1.1 | <4 | <−1.42 | <4 | <−1.42 | 5.33 ± 0.06 | −0.09 | 5.57 ± 0.10 | +0.15 | 5.48 ± 0.34 | +0.06 |
| Amlexanox | 7.63 ± 0.07 | 5.86 ± 0.05*** | −1.77 | 5.66 ± 0.27*** | −1.97 | 6.93 ± 0.06** | −0.7 | 7.50 ± 0.12 | −0.13 | 7.59 ± 0.15 | −0.04 | 7.23 ± 0.18 | −0.4 |
| Doxantrazole | 6.51 ± 0.02 | 5.35 ± 0.09*** | −1.16 | 5.28 ± 0.25*** | −1.23 | 4.98 ± 0.16*** | −1.53 | 6.37 ± 0.12 | −0.14 | 7.15 ± 0.13** | +0.64 | 6.70 ± 0.47 | +0.19 |
| Pemirolast | 7.02 ± 0.03 | 5.78 ± 0.08*** | −1.24 | 5.05 ± 0.46*** | −1.97 | 5.97 ± 0.04*** | −1.05 | 6.86 ± 0.09 | −0.16 | 7.49 ± 0.12** | +0.47 | 6.64 ± 0.29* | −0.38 |
N/A, not applicable, as pemirolast lacked potency at wild-type human GPR35a.
*
P < 0.05; **P < 0.01; ***P < 0.001: pEC50 significantly different from corresponding wild type.