Phosphorylation Sites in the Amino-Terminal Region of Mouse p53

• Published in: Proceedings of the National Academy of Sciences - PNAS 1992-05, Vol.89 (10), p.4231-4235
• Main Authors: Wang, Yeong, Eckhart, Walter
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino acids; Analytical, structural and metabolic biochemistry; Animals; Bacteria; Biochemistry; Biological and medical sciences; CDC2 Protein Kinase - metabolism; Cell Line; Cell lines; Cloning, Molecular; COS cells; Cytomegalovirus; DNA; Electrophoresis, Gel, Two-Dimensional; Fundamental and applied biological sciences. Psychology; Gene expression regulation; Genetic mutation; HeLa Cells; Humans; identification; Mice; Miscellaneous; Molecular Sequence Data; p53 protein; Peptide Mapping; Phosphates - metabolism; Phosphopeptides - isolation & purification; Phosphorylation; protein p53; Proteins; Recombinant Proteins - isolation & purification; Recombinant Proteins - metabolism; Restriction Mapping; Rodents; Serine; site-directed mutagenesis; sites; Transfection; Tumor Suppressor Protein p53 - genetics; Tumor Suppressor Protein p53 - isolation & purification; Tumor Suppressor Protein p53 - metabolism
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.89.10.4231

Phosphorylation is an attractive mechanism for regulating the functions of p53. The p34cdc2kinase, which is involved in regulation of the cell cycle, phosphorylates serine-315 of human p53 in vitro. Casein kinase II phosphorylates serine-389 of mouse p53 in vitro. The amino-terminal region of mouse p53 contains a cluster of potential serine phosphorylation sites. Those sites have been proposed to be sites for phosphorylation by a double-stranded DNA-dependent kinase (DNA-PK) from HeLa cells and can be dephosphorylated by protein phosphatase 2A. To identify in vivo phosphorylation sites in the amino-terminal region of mouse p53, we mutated potential phosphorylation sites and analyzed the mutant proteins by tryptic phosphopeptide mapping. We identified serine-7, -9, -18, and -37 as in vivo phosphorylation sites. We further showed that mouse p53 expressed in bacteria is phosphorylated by DNA-PK on aminoterminal serine residues in vitro.