Fig. 3: DRD2 activation triggers β-arrestin2 to bind and dimerize PKM2.

a The PKM2 dimer and tetramer formation in primary astrocytes pretreated with 100 ng ml⁻¹ PTX for 20 min and then stimulated with 10 µM quinpirole for 12 h was analyzed by BN-PAGE, and total PKM2 was detected by immunoblotting with actin as a loading control. Three independent experiments per condition. b Primary astrocytes transfected with β-arrestin1- or β-arrestin2-specific siRNA were stimulated with 10 µM quinpirole for 12 h. PKM2 dimer and tetramer formation analyzed by BN-PAGE and total PKM2 detected by immunoblotting with actin as a loading control. Three independent experiments per condition. c–i Primary astrocytes from β-arrestin2-knockout mice were stimulated with 10 µM quinpirole for 12 h. PKM2 dimer and tetramer formation analyzed by BN-PAGE and total PKM2 detected by immunoblotting with actin as a loading control (c). Immunoblot analysis of PKM2 in cell lysates immunoprecipitated with a Nrf2 antibody (d). PKM2 and Nrf2 proximity ligation signals (e). Amount of anti-Nrf2-immunoprecipitated DNA detected by qRT-PCR with primers flanking the Gclc and Gclm promoter regions (f). Gclc and Gclm mRNA detected by qRT-PCR (g). Immunoblotting with actin as a loading control (h) and GSH levels (i). Immunoblotting and qRT-PCR: three independent experiments; GSH assay: six independent experiments. Scale bar, 10 µm. Data are presented as the mean ± s.e.m. NS, not significant. Student’s two-tailed unpaired t-test (f, g and i). Source data are provided as a Source Data file.