Fig. 10.

Effects of expressing a doxycycline-inducible drug-resistant CDK7 on System A adaptation in response to AA withdrawal.

HeLa S3 cells stably expressing doxycycline-inducible FLAG-WT CDK7 or FLAG-C132S CDK7 constructs (or empty vector (EV)) were treated with (+) or without (−) doxycycline (2 μg/ml) for 24 h. Resulting cell lysates were subjected to SDS-PAGE and immunoblotted using the antibodies indicated (A). Alternatively, doxycycline treated cells were deprived of amino acids (−) or not (+) for 6 h in the presence or absence of 1 μM THZ-1 prior to measurement of Me-AIB uptake rates (A). In addition, wild type HeLa cells were starved of amino acids (−) or not (+) for 6 h in the presence or absence of 1 μM THZ-1 and the indicated concentrations of THZ531 (B). Quantified values are presented as the mean ± S.E.M. (n = 3). *, P < 0.05; NS, not significant relative to corresponding amino acid containing control unless otherwise indicated.