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
Ligand	Wild-Type	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.