Monoclonal Antibody to Phosphorylated p53
The gene for the tumor suppressor protein p53 encodes a nuclear phosphoprotein that is altered by mutation or deletion in about 50% of human tumors. When single point mutations modify p53 structure and function, post-translational modifications of mutated p53 molecules are expected to interfere even more strongly with its function of controlling cell growth and division. The most prominent post-translational modification of p53 is phosphorylation at one or more of many sites along the protein. Wistar researchers developed a double-phosphorylated peptide that is phosphorylated at the Ser378 and Ser392 sites of human p53. This peptide was then used to generate a highly sensitive monoclonal antibody (mAb p53-18) to p53 protein. This antibody can be used to distinguish the phosphorylated from the non-phosphorylated forms of p53. Since sera from cancer patients preferentially label the double-phosphorylated p53 peptide, the mAb p53-18 may be useful in developing cancer diagnostics.