The specific antibodies used in this study are as follows: Anti-(-tubulin (mouse monoclonal, 1:1000, Sigma), Anti-Cyclin A (rabbit polyclonal, 1:500, Santa Cruz), Anti-Cyclin D1 (mouse monoclonal, 1: 200, Santa Cruz), Anti-Cyclin B1 (rabbit polyclonal, 1: 3000, Santa Cruz), Anti-Az1 (rabbit polyclonal, 1: 2000, a gift from John Mitchell, Northern Illinois University), Anti-FLAG M2 (mouse monoclonal, 1: 2000, Stratagene), Anti-FLAG (rabbit polyclonal, 1:3000, Sigma), Anti-HA (mouse monoclonal, 1:2000, Sigma), Anti-HA (rabbit polyclonal, 1:400, Santa Cruz), Anti-His (mouse monoclonal, 1:1000, Sigma), Aurora-A (anti-IAK1, mouse monoclonal, 1:2000, Pharmingen) and anti-p53 (mouse monoclonal,1:2000, Santa Cruz). All HRP-conjugated secondary antibodies (Pierce) were used at 1:8000 dilution.