Biomolecules & Therapeutics : eISSN 2005-4483 / pISSN 1976-9148

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Fig. 4. Involvement of helix 8 in β-arrestin-1/2-mediated desensitization of D1R-Gs signaling. HEK293 cells were stably transfected with the shRNAs for human β-arrestin1 and β-arrestin2 to generate β-arrestin-1/2 knockdown (βArr1/2-KD) cells (). About 80–90% cellular β-arrestin1 and β-arrestin2 were knocked down in β-arrestin KD cells (). Control and βArr1/2-KD cells were transfected with indicated receptor constructs along with the plasmids required for the determination of cellular cAMP. Receptor expression levels were maintained between 2.1–2.7 pmol/mg protein. (A) Control and βArr1/2-KD cells expressing D1R were treated with increasing concentrations of SKF38393. Forskolin (10 μM)-induced increase in CRE-luci was calculated as 100%, and SKF38393-induced increase in CRE-luci was normalized to it. The same protocols were applied for (D) (D1R-D2H8), (E) (D1R-K8.52A), and (F) (D1R-T8.56A/G8.59L). (B) Control and βArr1/2-KD cells expressing D2R were treated with 2 μM forskolin and increasing concentrations of quinpirole. The same protocols were applied for (C) (D2R-D1H8). Error bars represent STDEV.
Biomolecules & Therapeutics 2019;27:514~521
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