FIG. 2.

Requirement for the phosphotyrosines of Stat6 in GST pulldown assays. (A) Nuclear extracts from IL-4-stimulated I.29μ B cells were treated with TCPTP in the presence (lanes c, e, and g) or absence (lanes d, f, and h) of vanadate prior to incubation with the indicated GST fusion proteins. Lanes a and b show the input Stat6 in the pretreated nuclear extracts (10 μg). (B) Purified rStat6 was left untreated (lanes c, e, and g) or pretreated with TCPTP (lanes d, f, and h) prior to incubation with GST fusion proteins. rStat6 was then used for binding to the indicated GST fusion proteins. Lanes a and b show the inputs of pretreated rStat6 (1 ng). The bound Stat6 and rStat6 were resolved by SDS–10% PAGE, followed by Western blotting with anti-Stat6 antibody. The lanes are from the same blot, autoradiographed for the same time.