title: Phosphorylation of p53 modifies sensitivity to ionizing radiation.
abstract: Phosphorylation is an important modification involved in the control of p53 activity. We examined the relationship between p53 phosphorylation and cell radiosensitivity. We prepared H1299 cells (p53-null) with various mutations of p53 at three sites (serine 15, 20 and 46) and examined the radiosensitivity of the cells. In three mutant forms of p53--S15A, S20A and S46A--serine was converted to alanine at these sites to prevent phosphorylation, and in two other mutant forms, S15D and S20D, serine was converted to aspartic acid to mimic phosphorylation. H1299 cells were more radioresistant than cells with wild-type p53. Cells with the S15A and S46A mutant forms of p53 were radiosensitive, whereas those with the S15D, S20A and S20D forms showed medium radiosensitivity. Thus the sensitivity of cells to ionizing radiation varies according to the site of phosphorylation of p53.
authors: Department of Radioisotope Medicine, Atomic Bomb Disease and Hibakusha Medicine Unit, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 12-4 Sakamoto 1-chome, Nagasaki 852, Japan. okaichi@nagasaki-u.ac.jp
authors: Kumio
authors: K
authors: Okaichi
authors: Kanako
authors: K
authors: Nose
authors: Takako
authors: T
authors: Kotake
authors: Nanaka
authors: N
authors: Izumi
authors: Takashi
authors: T
authors: Kudo
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism / Q000532:radiotherapy; D045744:Cell Line, Tumor; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000532:radiotherapy; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D011836:Radiation Tolerance; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: D016159:Tumor Suppressor Protein p53