Figure 5.

Effect of kaempferol on the ErbB3 signaling pathway. HT-29 cells were treated with 0 or 60 μmol/L kaempferol for 2 hours and lysed after 0, 1, or 5 minutes of stimulation with 20 μg/L heregulin (HRG)-β. (A) Total cell lysates were incubated with anti-ErbB3 antibody and the immune complexes were precipitated with protein A-Sepharose. The immunoprecipitated proteins were subjected to Western blot analysis and in vitro phosphatidylinositol 3-kinase (PI3K) assay as described in Figure 4. (B) Total cell lysates were subjected to Western blot analysis with their relevant antibodies. ERK, extracellular regulated kinase; IP, immunoprecipitation; PIP, phosphatidylinositol 3-phosphate; WB, western blot analysis.