FIG. 3.

Lactacystin does not affect the expression of endogenous CDK9. T98G cells were serum starved and restimulated as described in Materials and Methods. The cells were collected 16 and 20 h after restimulation. One set of samples was treated with lactacystin for 5 h before the cells were collected (11 and 15 h after restimulation). The levels of CDK9 and p27 proteins in extracts of cells treated with lactacystin or vehicle were determined by Western blot analysis using anti-CDK9 and anti-p27 antibodies, respectively. Lac/5h, treatment with lactacystin for 5 h; SS, serum starved.