Ser175 is not required for P-TEFb formation and the assembly of the 7SK snRNP complex.

Abstract

<p>(A) FLAG-CDK9 wildtype, S175A, S175D, T186A, or T186D were stably expressed in Jurkat 2D10 cells using the MSCV retroviral expression system. Western blotting analysis was performed on the whole cell extracts (left panels) and the corresponding anti-FLAG-CDK9 immunoprecipitates (right panels) using antibodies against CycT1, CDK9 and the 7SK RNP protein components HEXIM1 and LARP7. (B) Quantitative analysis of protein levels. Protein concentrations were estimated by densitometry of the Western blots and normalized against total immunoprecipitated CDK9. The data are from five independent experiments. Error bars: ± standard error of the mean.</p