FIG. 1.

Pin1 is overexpressed in Tax-expressing cell lines. (A) Cell-endogenous Pin1 from Jurkat (lane 1), H9 (lane 2), C8166-45 (C81; lane 3), and MT4 (lane 4) cells was assayed using anti-Pin1. Tax protein was assessed using a monoclonal anti-Tax. Equal loading of the cell extracts was verified with anti-actin. (B) Induction of Pin1 expression in JPX9 cells. Whole-cell lysates from JPX9 cells treated with CdCl₂ for 24 h (lane 2) and 48 h (lane 3) were analyzed by immunoblotting with anti-Pin1 and anti-Tax. Equal loading was verified with anti-tubulin. (C) Whole-cell lysates of 293T cells transfected with different GFP-Tax plasmids were immunoblotted for Pin1 with anti-Pin1 and for Tax with anti-Tax. Equal loading of cell extracts was verified with anti-actin. Tax and Tax S258A, a point mutant that cannot activate NF-κB, induced Pin1 expression (lanes 2 and 3), while Tax L320G, a CREB activation-deficient mutant, did not induce Pin1 expression (lane 4). (D) 293T cells were cotransfected with pCDNA 3.0 and E2F-Luc plasmid (lane 1), plus 2 μg of Tax (lane 2), Tax S258A (lane 3), or Tax L320G (lane 4). The same amounts of cellular extracts were assayed for Luc. Tax and Tax S258A activated E2F-Luc (lanes 2 and 3), but Tax L320G did not (lane 4). α, anti: IB, immunoblotting.