. Author manuscript; available in PMC: 2022 Jun 2.

Published in final edited form as: ACS Chem Neurosci. 2021 May 11;12(11):1873–1884. doi: 10.1021/acschemneuro.0c00712

Table 1.

Arrestin recruitment: requirement for overexpressed GRK2

Receptor	Arrestin Recruitment
	+ GRK2^a		No GRK2
	−LogEC₅₀	E_max (% of WT+GRK2)	−LogEC₅₀	E_max (% of WT+GRK2)
D2_L-WT	7.69 ± 0.05	100 ± 2	6.85 ± 0.05^†††	59 ± 4^†††
D2_L-I²¹²F	8.06 ± 0.03**	56 ± 1*** (−44%)	7.22 ± 0.08**^,†††	16 ± 1***^,††† (−73%)
D2_S-WT	7.83 ± 0.01	100 ± 3	7.20 ± 0.13^†††	59 ± 2^†††
D2_S-I²¹²F	8.24 ± 0.04**	73 ± 2*** (−27%)	7.59 ± 0.09*^,†††	21 ± 0.4***^,††† (−66%)

Quinpirole potency is shown as −logEC₅₀. E_max was calculated by subtracting basal response from maximal response at 10 min after adding the substrate coelenterazine h, and is shown as the percentage of D2-WT with added GRK2. For D2-I²¹²F, the percent reduction compared to the corresponding D2-WT E_max is included in parentheses. N = 3–4 independent experiments for each condition. Data are presented as mean ± SEM.

From the dataset described in van der Weijden et al. (8), except after 10 min instead of 20 min of agonist stimulation. Statistical differences were calculated by 2-way ANOVA followed by Turkey’s post-hoc test (*p<0.05, **p<0.01, ***p<0.001 compared to D2-WT; ^†††p<0.001 compared to the corresponding +GRK2 condition).