Protein phosphatase 2A (PP2A) holoenzymes regulate death-associated protein kinase (DAPK) in ceramide-induced anoikis

Ryan C. Widau, Yijun Jin, Shelley A. Dixon, Brian E. Wadzinski, Patricia Gallagher

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

The tumor suppressor, death-associated protein kinase (DAPK), is a Ca 2+/calmodulin-regulated Ser/Thr kinase with an important role in regulating cytoskeletal dynamics. Autophosphorylation within the calmodulin-binding domain at Ser-308 inhibits DAPK catalytic activity. Dephosphorylation of Ser-308 by a previously unknown phosphatase enhances kinase activity and proteasome-mediated degradation of DAPK. In these studies, we identified two holoenzyme forms of protein phosphatase 2A (PP2A), ABαC and ABδC, as DAPK-interacting proteins. These phosphatase holoenzymes dephosphorylate DAPK at Ser-308 in vitro and in vivo resulting in enhanced kinase activity of DAPK. The enzymatic activity of PP2A also negatively regulates DAPK levels by enhancing proteasome-mediated degradation of the kinase. Overexpression of wild type DAPK induces cell rounding and detachment in HEK293 cells; however, this effect is not observed following expression of an inactive DAPK S308E mutant. Finally, activation of DAPK by PP2A was found to be required for ceramide-induced anoikis. Together, our results provide a mechanism by which PP2A and DAPK activities control cell adhesion and anoikis.

Original languageEnglish
Pages (from-to)13827-13838
Number of pages12
JournalJournal of Biological Chemistry
Volume285
Issue number18
DOIs
StatePublished - Apr 30 2010

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Death-Associated Protein Kinases
Anoikis
Protein Phosphatase 2
Holoenzymes
Ceramides
Phosphotransferases
Proteasome Endopeptidase Complex
Calmodulin
Phosphoric Monoester Hydrolases
Degradation
HEK293 Cells
Cell adhesion
Cell Adhesion
Tumors

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

Cite this

Protein phosphatase 2A (PP2A) holoenzymes regulate death-associated protein kinase (DAPK) in ceramide-induced anoikis. / Widau, Ryan C.; Jin, Yijun; Dixon, Shelley A.; Wadzinski, Brian E.; Gallagher, Patricia.

In: Journal of Biological Chemistry, Vol. 285, No. 18, 30.04.2010, p. 13827-13838.

Research output: Contribution to journalArticle

Widau, Ryan C. ; Jin, Yijun ; Dixon, Shelley A. ; Wadzinski, Brian E. ; Gallagher, Patricia. / Protein phosphatase 2A (PP2A) holoenzymes regulate death-associated protein kinase (DAPK) in ceramide-induced anoikis. In: Journal of Biological Chemistry. 2010 ; Vol. 285, No. 18. pp. 13827-13838.
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