FIG. 1.

TAZ is identified as a binding partner for all polyomavirus T antigns. (a) A “flipped” bait with wild-type sT fused through its C terminus to the Gal4 DNA-binding domain was used to perform yeast two-hybrid screening. (b) Target TAZ combines a C-terminal PDZ-binding motif, a 14-3-3-binding sequence, and a WW domain. (c) Transfections and pull-down assays with GST-TAZ. Wild-type and mutant D2N and Δ2-4 versions of T antigen cDNAs were cotransfected into NIH 3T3 cells along with GST-TAZ. Extracts of transfected cells were incubated with GST beads. Bound proteins were eluted and analyzed by Western blotting with F4 monoclonal antibody recognizing all three T antigens. Wild-type T antigens are shown to the left of the panels; mutant T antigens are shown to the right in parentheses. D2N sT bound TAZ roughly 60% as well as wild-type sT. The mutation Δ2-4 effectively abolished binding of TAZ by each of the T antigens. A total of 5% of the cell lysate was loaded in the input lanes.