Figure 6

Role of the PI3K pathway in mediating differences between serum and GF response. A cluster view of the 1,379 Class II clones showing differential expression between serum and other GF treatment groups is shown. The right hand side shows the expression profiles of these Class II genes in foreskin fibroblasts when quiescent cells were first treated with either LY294002 (a PI3K inhibitor) or U0126 (a MAPK pathway inhibitor) before growth stimulation with serum or growth factors for LY294002 or serum for U0126. Inhibition of the PI3K pathway, but not the MAPK pathway, converted the expression profiles of Class II genes after serum treatment to a pattern similar to that after GF treatment.