Fig. 3.

Expression levels of the total and phosphorylated Chk1 protein kinase at Ser317 by Western blot analysis (a). Data shown are representative of three independent experiments. The relative levels of Chk1 (total) and Chk1-P (Ser317) after normalization for β-tubulin, as determined by densitometry analysis of the bands, are shown in the histogram (b; the pixel values [pv; 1–255] categorized according to densitometry analysis of the bands intensities and expressed in arbitrary units [a.u.]). Columns, mean from three independent experiments; bars, SD. * P < 0.001, compared with control (Mann–Whitney U test; U = 0); filled diamond, P < 0.001, compared with control (Mann–Whitney U test; U = 18.5); filled square, P < 0.001, compared control (Mann–Whitney U test; U = 71.5)