Anti-phospho-p53 (Ser20) (Tumor Suppressor Protein, Oncogene Protein)

The p53 tumor suppressor protein plays a major role in cellular response to DNA damage and other genomic aberrations. Activation of p53 can lead to either cell cycle arrest and DNA repair or apoptosis (1). p53 is phosphorylated at multiple sites in vivo and by several different protein kinases in vitro (2,3). DNA damage induces phosphorylation of p53 at Ser15 and Ser20 and leads to reduced interaction of p53 with its negative regulator, oncoprotein MDM2 (4). MDM2 inhibits the accumulation of p53 by targeting it for ubiquitination and proteasomal degradation (6,7). p53 can apparently be phosphorylated by ATM, ATR and DNA-PK at Ser15 and Ser37. The phosphorylations impair the ability of MDM2 to bind p53, promoting both the accumulation and functional activation of p53 in response to DNA damage (4,5). Chk2 and Chk1 can phosphorylate p53 at Ser20, enhancing its tetramerization, stability and activity (8,9). p53 is phosphorylated at Ser392 in vivo (11,12) and by CAK in vitro (12). Phosphorylation of p53 at Ser392 is altered in human tumors (14) and has been reported to influence the growth suppressor function, DNA binding and transcriptional activation of p53 (10,11,13). p53 is phosphorylated at Ser6 and Ser9 by ck1delta and ck1epsilon both in vitro and in vivo (10,15). Phosphorylation of p53 at Ser46 is important in regulating the ability of p53 to induce apoptosis (16). Applications: Suitable for use in ELISA and Western Blot. Other applications not tested. Recommended Dilution: Western Blot: 1:1000. Incubate membrane with diluted antibody in 1X TBS, 5% BSA, 0.1% Tween-20 at 4°C with gentle shaking, overnight., Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4°C for short-term only. For long-term storage, store at -20°C. Aliquots are stable for at least 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.