Fig. 4: P38-Pin1 pathway regulates composition of the Kv4.2-DPP6 complex.

a P38 inhibitor SB203580 blocked PTZ-induced Kv4.2-DPP6 dissociation while MEK inhibitor SL327 did not. Mouse forebrain lysates with or w/o SB203580 (20 mg/kg, i.p., 20 min) or SL327 (30 mg/kg, i.p., 20 min) or PTZ administration (60 mg/kg, i.p., 20 min) were immunoprecipitated with anti-Kv4.2 antibody. PTZ-injected mice showed decreased Kv4.2-DPP6 binding, blocked by preinjection of SB203580 but not SL327. n = 5 for each group. b Pin1 inhibitor juglone blocked PTZ-induced Kv4.2-DPP6 dissociation. Forebrain lysates with or w/o juglone (15 mg/kg, i.p., 15 min) or PTZ administration (60 mg/kg, i.p., 20 min) were immunoprecipitated with an anti-Kv4.2 antibody. PTZ-injected mice showed decreased Kv4.2-DPP6 binding while juglone-preinjected mice exhibited normal Kv4.2-DPP6 binding. n = 4 for ctl, 5 for PTZ and Juglone/PTZ. c Pin1C113S mutant blocked AMPA-induced Kv4.2-DPP6. Cultured cortical neurons infected with GFP or Pin1C113S lentivirus were treated with 50uM AMPA for 15 min and processed for immunoprecipitation with anti-Kv4.2 antibody. AMPA treatment reduced Kv4.2-DPP6 binding in GFP but not in Pin1C113S infected neurons. n = 6 for each group. d Seizure-induced Pin1-Kv4.2 association is abolished in Kv4.2TA mice. GST or GST-Pin1-linked beads were incubated with brain lysates from WT and Kv4.2TA mice with or without PTZ administration (60 mg/kg, i.p., 15 min). n = 4 WT/Ctl, WT/PTZ and Kv4.2TA/Ctl, n = 3 for Kv4.2TA/PTZ. e Seizure-induced Pin1-Kv4.2 association is abolished in Kv4.2TA mice. Forebrain lysates from WT and Kv4.2TA mice were immunoprecipitated with rabbit anti-Kv4.2 antibody, with or without PTZ administration (60 mg/kg, i.p., 15 min). Pin1-Kv4.2 association is induced by PTZ in WT but abolished in Kv4.2TA mice. n = 4 each group. f PTZ-induced Kv4.2-DPP6 dissociation is abolished in Kv4.2TA mice. Forebrain lysates from WT and Kv4.2TA mice with or w/o PTZ administration (60 mg/kg, i.p., 20 min) were immunoprecipitated with anti-Kv4.2 antibody. PTZ treatment decreased Kv4.2-DPP6 binding in WT but not in Kv4.2TA mice. n = 3 for each group. Data are presented as mean ± SEM. Paired T-test, **p < 0.01, **p < 0.01 vs ctl, ^##p < 0.01 Kv4.2TA vs WT, ***p < 0.001.