Table 1. Effects of i3 Loop Deletions on the Sensitivity of M3R to Gβ5-RGS7^a.

	M3R			M3R with Gβ5-RGS7
	nb	Emaxc,d	–log EC50d,e	nb	Emaxc,d	–log EC50d,e
WT	80	100 ± 3.94	6.35 ± 0.13	86	64 ± 3.15	6.00 ± 0.16
M3RΔ304–325	60	101 ± 3.66	6.57 ± 0.14	67	82 ± 3.11	6.56 ± 0.13
M3RΔ325–345	63	70 ± 2.78	6.82 ± 0.13	67	73 ± 2.37	6.24 ± 0.11
M3RΔ370–390	64	106 ± 2.62	6.95 ± 0.08	67	56 ± 1.60	6.66 ± 0.10
M3RΔ304–390	36	61 ± 4.05	5.61 ± 0.23	36	68 ± 10.33	4.90 ± 0.43

^aCCh-induced Ca²⁺ signaling was measured by FLIPR in cells transfected with different M3R i3 loop deletion mutants as described in the legend of Figure 1 and Experimental Procedures.

^bn is the number of points analyzed (two independent experiments).

^cE_max is the maximal change in well fluorescence expressed as a percentage of that of WT M3R (=100%).

^dMean ± the standard error of the mean.

^e–Log EC₅₀ (in molar) is the negative logarithm of the agonist concentration that produces the half-maximal effect.