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. Author manuscript; available in PMC: 2009 Jul 3.
Published in final edited form as: Oncogene. 2008 Mar 10;27(29):4065–4074. doi: 10.1038/onc.2008.48

Figure 7. Oxidative stress stimulates wortmannin sensitive proteolysis of p21.

Figure 7

H1299-EGFp21 cells were exposed to room air or hyperoxia for 24 hours in the presence of doxycycline (2 µg/ml) to induce EGFp21 fusion protein. Cycloheximide (50 µg/ml) was added to inhibit new protein synthesis and cells were returned to room air or hyperoxia. (a) Cell lysates harvested following cycloheximide were immunoblotted with antibodies against EGFP or actin. (b) Graph of EGFp21 band intensity from a representative experiment in which cells were exposed to room air (filled triangles) or hyperoxia (open triangles). (c) H1299-EGFp21 cells were exposed to hyperoxia for 24 hours, doxycycline (2 µg/ml) to induce EGFp21 fusion protein, and the absence or presence of wortmannin to inhibit PIKK activity. Cycloheximide (50 µg/ml) was added to inhibit new protein synthesis and EGFp21 protein levels determined by western blot analysis. (d) Graph of EGFp21 band intensity from a representative experiment in which cells were exposed to hyperoxia (filed squares) or hyperoxia and wortmannin (open squares).