Dephosphorylation of Bcl-2 by protein phosphatase 2A results in apoptosis resistance

Siro Simizu, Yuki Tamura, Hiroyuki Osada

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38 Citations (Scopus)


The anti-apoptotic protein, Bcl-2 was phosphorylated at the Ser-87 residue in normal human blood cells, while it was not phosphorylated in tumor cells. We identified protein phosphatase 2A (PP2A) as a Bcl-2-associated phosphatase that is responsible for dephosphorylation of Bcl-2 in tumor cell lines. Treatment of the tumor cells with a PP2A inhibitor resulted in the appearance of Bcl-2 phosphorylation at Ser-87. This observation suggests that Bcl-2 is constitutively phosphorylated, but is immediately dephosphorylated by PP2A in tumors. Phosphorylation of Bcl-2 protein at the Ser-87 residue resulted in a reduction in anti-apoptotic function in human tumor cell lines. Thus, not only the expression level, but also the dephosphorylation status may have important implications for the oncogenic activity of Bcl-2.

Original languageEnglish
Pages (from-to)266-270
Number of pages5
JournalCancer science
Issue number3
Publication statusPublished - 2004 Mar
Externally publishedYes

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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