Abnormal stability of wild-type p53 protein in a human lung carcinoma cell line

Motohiro Yamauchi, Keiji Suzuki, Seiji Kodama, Masami Watanabe

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


We report here that ectopically expressed wild-type p53 protein showed more than 6 times longer half-life than normal human fibroblasts in NCl-H1299, a widely used cell line derived from non-small cell lung carcinoma lacking the expression of p53 protein. We found no abnormality in the phosphorylation and ubiquitination of p53, and the expression levels of MDM2. Although proteasome activity measured in vitro was not significantly different between the tumor cell line and normal human fibroblasts, proteasome inhibitors, ALLN, MG115, and MG132, did not accumulate p53 protein in the tumor cell line, but did accumulate p53 in normal human cells. These results provide a novel mechanism, by which p53 is stabilized in tumor cells, and they suggest that a mediator should exist between ubiquitinated p53 and proteasome, which may be defective in H1299 cells.

Original languageEnglish
Pages (from-to)483-488
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number2
Publication statusPublished - May 6 2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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