14-3-3Sigma is required to prevent mitotic catastrophe after DNA damage

Nature. 1999 Oct 7;401(6753):616-20. doi: 10.1038/44188.


14-3-3Sigma is a member of a family of proteins that regulate cellular activity by binding and sequestering phosphorylated proteins. It has been suggested that 14-3-3sigma promotes pre-mitotic cell-cycle arrest following DNA damage, and that its expression can be controlled by the p53 tumour suppressor gene. Here we describe an improved approach to the generation of human somatic-cell knockouts, which we have used to generate human colorectal cancer cells in which both 14-3-3sigma alleles are inactivated. After DNA damage, these cells initially arrested in the G2 phase of the cell cycle, but, unlike cells containing 14-3-3sigma, the 14-3-3sigma-/- cells were unable to maintain cell-cycle arrest. The 14-3-3sigma-/- cells died ('mitotic catastrophe') as they entered mitosis. This process was associated with a failure of the 14-3-3sigma-deficient cells to sequester the proteins (cyclin B1 and cdc2) that initiate mitosis and prevent them from entering the nucleus. These results may indicate a mechanism for maintaining the G2 checkpoint and preventing mitotic death.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 14-3-3 Proteins
  • Cell Cycle Proteins / physiology
  • Cloning, Molecular
  • Cyclin B / physiology
  • Cyclin B1
  • DNA Damage*
  • G2 Phase / physiology
  • Humans
  • Mitosis / physiology*
  • Proteins / genetics
  • Proteins / physiology*
  • Tumor Cells, Cultured
  • Tyrosine 3-Monooxygenase*
  • cdc25 Phosphatases / physiology


  • 14-3-3 Proteins
  • CCNB1 protein, human
  • Cell Cycle Proteins
  • Cyclin B
  • Cyclin B1
  • Proteins
  • Tyrosine 3-Monooxygenase
  • CDC25C protein, human
  • cdc25 Phosphatases