Tat treatment enhances interaction between NR2A and nNOS. (A) NR2A was immunoprecipitated (IP) from lysates of control, untreated cultures (time 0), or cultures treated with tat or tat plus CCL2 for 5, 10, 15, 30, 45, 60, and 180 min, and precipitates were analyzed by Western blotting (WB) for nNOS interaction. Total protein lysate was used as a loading control (Input). (B) Densitometric analysis (n = 3) of nNOS abundance in the CoIP relative to input. No or low interaction between NR2A and nNOS was found in control cells. Tat treatment resulted in nNOS association with NR2A that was maximal between 30 and 60 min after tat treatment (∗, P < 0.05 vs. control; #, P < 0.05 vs. 10–30 min tat treated). CCL2 cotreatment significantly inhibited tat-induced NR2A/nNOS complex formation (&, P < 0.05 vs. tat alone).