Association of Pak3 with Tax and CRTC1 in cultured cells. (A and B) Pak3 interacts with Tax. HEK293T cells were co-transfected with expression plasmids for Tax and Flag-Pak3. Pak3 was immunoprecipitated with anti-Flag. The precipitates were analyzed by Western Blotting using anti-Flag (A) and anti-Tax (B) to detect Pak3 and Tax, respectively. (C and D) M5 mutant of Pak3 associates with Tax. (E) Pak3 interacts with Tax and CRTC1. HEK293T cells were co-transfected with expression plasmids for Flag-Pak3, Tax and CRTC1-V5. CRTC1 was immunoprecipitated with anti-V5. CRTC1, Pak3 and Tax in the precipitates were detected with anti-V5, anti-Flag and anti-Tax antibodies, respectively.