TIP-1 suppressed p53 activation after irradiation.

<p>D54 cells with an ectopic expression <i>(A)</i> or shRNA depletion <i>(B)</i> were mock treated or irradiated at 5 Gy, whole cell lystates were collected at the indicated time points post the treatment for western blot analyses to profile pathway mediators that sense, transduce, or execute cellular response to DNA damage. <i>C)</i> Semi-quantification of p53 upon the band density on blots using a densitometer. Significance was determined by comparing the denoted group to the respective vector control with the same treatment, respectively. *<i>p</i><0.05, t-test. <i>D)</i> Analyses of p53 ubiquitination. Cells were mock treated or with IR (5 Gy). MG132 was added at 8 hours post the treatment and incubated for 4 more hours before the cell lysates were collected to analyze the p53 ubiquitination. The ubiquitinated p53 protein was immunoprecipitated with antibody against p53 and blotted with ubiquitin-antibody after the proteins were separated with SDS-PAGE. The representative image shows the ubquitinated p53 ladder (pointed with arrows), as well as overall p53, TIP-1 and actin in each cell lysate.