Bcr-Abl induces the small Jab1 complex through MAPK and PI3K pathways. (A) K562 cells were treated with the chemicals indicated at the top of panel A for 8 hours. Cell lysates were analyzed by native-PAGE (first and second rows) and SDS-PAGE (third to sixth rows), followed by immunoblotting using antibodies against Jab1, p27, γ-tubulin, and Cul1. The relative amounts of p27 are presented as the ratio of p27–γ-tubulin and calculated with the level of untreated K562 cells as 1.0. Cur. indicates curcumin; Stau., staurosporine. (B) K562 cells were treated with DMSO, STI571 (STI), PD-98059 (PD), Wortmannin (Wort.), and the mixture of chemicals indicated for 8 hours. Cell lysates were separated by native-PAGE (first and second rows) and SDS-PAGE (third to sixth rows) and analyzed by immunoblotting using antibodies against Jab1, p27, γ-tubulin, and Cul1. The relative amounts of p27 are presented as the ratio of p27–γ-tubulin and calculated with the level of untreated K562 cells as 1.0. (C) K562 cells, able to produce a dominant-negative form of Ras (N17) on addition of IPTG, were treated with IPTG for 24 hours. Cell lysates were separated by native-PAGE (first and second rows) and SDS-PAGE (third to fifth rows), and analyzed by immunoblotting using antibodies against Jab1, p27, and γ-tubulin.