Mapping the Tax-augmenting domain in Pak3. (A) A diagram of Pak3 truncated mutants. (B) Expression of Pak3 mutants. Protein expression in HeLa cells was detected by Western blotting with anti-myc and anti-α-tubulin antibodies. (C) Activity profile of Pak3 truncated mutants on Tax-induced LTR activation. Dual luciferase assays were carried out as in Figure 1.