Tax interacts with USP10. (A,B) 293T cells were transfected with a control plasmid (lanes 1, 4), Tax plasmid (lanes 2, 5), or TaxΔC plasmid (lanes 3, 6) together with (lanes 4-6) or without (lanes 1-3) an HA-USP10 plasmid. At 48 hours after transfection, the cell lysates were immunoprecipitated with anti-HA (A) or anti-Tax (B) antibodies, and the total lysates (input) and immunoprecipitates (IP) were characterized using a western blot analysis with anti-HA and anti-Tax antibodies. TaxΔC has a 4 amino acid deletion on the Tax C-terminus, the peptide of which is missing in the nonleukemogenic HTLV-2 Tax2, because the original goal was to isolate binding factors specific to Tax but not to Tax2. (C) The cell lysates prepared from HTLV-1–uninfected T cells (Jurkat; lanes 1-3) and HTLV-1–infected T cells (SLB-1; lanes 4-6) were immunoprecipitated with anti-Tax antibodies (lanes 3, 6) or control antibodies (lanes 2, 5). The input lysate and IP were characterized using a western blot analysis with anti-USP10 and anti-Tax antibodies. (D) Cell lysates were prepared from 7 HTLV-1–infected T-cell lines (lanes 1-7) and 3 HTLV-1–uninfected T-cell lines (lanes 8-10). The expressions of USP10, PABP1, G3BP1, Tax, and α-tubulin proteins were determined using a western blot analysis with the corresponding antibodies. (E) 293T cells were transfected with a Tax plasmid together with or without the HA-USP10 plasmid. The transfected cells were stained with anti-USP10 (green) and anti-Tax (red) antibodies. The nuclei were counterstained with Hoechst33258 (blue). The bar indicates 20 μm.