Protein extracts (30 mg) prepared with RIPA lysis buffer (50 mM Tris-HCl, 150 mM NaCl, 0.1% SDS, 1% NP-40, 0.5% sodium deoxycholate, 1 mM PMSF, 100 mM leupeptin, and 2 mg/mL aprotinin, pH 8.0) were resolved by a 10% SDS-PAGE gel, and transferred onto Immobilon-P PVDF transfer mem-braneS (Millipore, Bedford, MA) by electroblotting. After blocking with 5% non-fat milk, the membranes were probed with rabbit anti-CaMKII polyclonal, rabbit anti-phospho-CaMKII (Thr286) polyclonal, goat anti-actin polyclonal antibodies (Santa Cruz Biotechnology, Santa Cruz, CA), rabbit anti-CDK2 polyclonal, rabbit anti-phospho-CDK2 (Thr160) polyclonal, rabbit antiphospho-stathmin (Ser25) polyclonal antibodies (Abcam Inc., Cambridge, MA), rabbit anti-His-tag polyclonal, rabbit antistathmin polyclonal, rabbit anti-phospho-stathmin (Ser38) polyclonal, rabbit anti-phospho-stathmin (Ser16) polyclonal, rabbit anti-p44/42 MAPK polyclonal, mouse anti-phospho-p44/42 MAPK (Thr202/Tyr204) monoclonal antibodies (Cell Signaling, Danvers, MA), and mouse anti a-tubulin monoclonal antibodies (DM1A, Sigma, St. Louis, MO). Blots were then incubated with peroxidase-conjugated anti-mouse, anti-rabbit or anti-goat IgG (KPL, Gaithersburg, Maryland) for 1 h at room temperature at a 1:2000 dilution and then developed by using the SuperSignal West Pico Kit (Pierce Biotechnology, Rockford, IL).