Contribution of Bcl-2 phosphorylation to bak binding and drug resistance

Haiming Dai, Husheng Ding, X. Wei Meng, Sun Hee Lee, Paula A. Schneider, Scott H Kaufmann

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

Bcl-2 is phosphorylated on Ser70 after treatment of cells with spindle poisons. On the basis of effects observed in cells overexpressing Bcl-2 S70E or S70A mutants, various studies have concluded that Ser70 phosphorylation either enhances or diminishes Bcl-2 function. In the present study, the ability of phosphorylated Bcl-2, as well as the S70E and S70A mutants, to bind and neutralize proapoptotic Bcl-2 family members under cell-free conditions and in intact cells was examined in an attempt to resolve this controversy. Surface plasmon resonance indicated that phosphorylated Bcl-2, Bcl-2 S70E, and Bcl-2 S70A exhibit enhanced binding to Bim and Bak compared with unmodified Bcl-2. This enhanced binding reflected a readily detectable conformation change in the loop domain of Bcl-2. Furthermore, Bcl-2 S70E and S70A bound more Bak and Bim than wild-type Bcl-2 in pull-downs and afforded greater protection against several chemotherapeutic agents. Importantly, binding of endogenous Bcl-2 to Bim also increased during mitosis, when Bcl-2 is endogenously phosphorylated, and disruption of this mitotic Bcl-2/Bim binding with navitoclax or ABT-199, like Bcl-2 downregulation, enhanced the cytotoxicity of paclitaxel. Collectively, these results provide not only a mechanistic basis for the enhanced antiapoptotic activity of phosphorylated Bcl-2, but also an explanation for the ability of BH3 mimetics to enhance taxane sensitivity.

Original languageEnglish (US)
Pages (from-to)6998-7008
Number of pages11
JournalCancer Research
Volume73
Issue number23
DOIs
StatePublished - Dec 1 2013

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Drug Resistance
Phosphorylation
Aptitude
Surface Plasmon Resonance
Poisons
Paclitaxel
Mitosis
Down-Regulation

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

Cite this

Contribution of Bcl-2 phosphorylation to bak binding and drug resistance. / Dai, Haiming; Ding, Husheng; Meng, X. Wei; Lee, Sun Hee; Schneider, Paula A.; Kaufmann, Scott H.

In: Cancer Research, Vol. 73, No. 23, 01.12.2013, p. 6998-7008.

Research output: Contribution to journalArticle

Dai, Haiming ; Ding, Husheng ; Meng, X. Wei ; Lee, Sun Hee ; Schneider, Paula A. ; Kaufmann, Scott H. / Contribution of Bcl-2 phosphorylation to bak binding and drug resistance. In: Cancer Research. 2013 ; Vol. 73, No. 23. pp. 6998-7008.
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