Stat5 activation in mutant FdCP1 clones.

Nuclear extracts were prepared from cells (19-neo, 19-WT, 19-M1, and 19-M2 cells) treated with either GM-CSF or IL-3 as outlined in Figure1. The extracts were sequentially immunoblotted with a pan–Stat5-specific antibody (A) and Stat5 phospho-specific antibody (B). Mobility of p96 (Stat5a), p94 (Stat5b), p80 (truncated Stat5b), and p77 (truncated Stat5a) is indicated on the left margin of each panel.