(b) Ba/F3 cells expressing either myrPI(3) K-ER or myrPKB-ER were cytokine starved overnight and stimulated with 4-OHT. Relative mRNA levels of glutamine synthetase were analysed using quantitative rtPCR. Data are represented as mean ± s.e.m. normalized for B2M (n=4). *P0.05, **P0.01. 