Phosphodiesterase-8A binds to and regulates Raf-1 kinase

Kim M. Brown, Jon P. Day, Elaine Huston, Bastian Zimmermann, Kornelia Hampel, Frank Christian, David Romano, Selim Terhzaz, Louisa C.Y. Lee, Miranda J. Willis, David B. Morton, Joseph A. Beavo, Masami Shimizu-Albergine, Shireen A. Davies, Walter Kolch, Miles D. Houslay, George S. Baillie

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


V-raf-1 murine leukemia viral oncogene homolog 1 (Raf-1) is a key activator of the ERK pathway and is a target for cross-regulation of this pathway by the cAMP signaling system. The cAMP-activated protein kinase, PKA, inhibits Raf-1 by phosphorylation on S259. Here, we show that the cAMP-degrading phosphodiesterase-8A (PDE8A) associates with Raf-1 to protect it from inhibitory phosphorylation by PKA, thereby enhancing Raf-1's ability to stimulate ERK signaling. PDE8A binds to Raf-1 with high (picomolar) affinity. Mapping of the interaction domain on PDE8A using peptide array technology identified amino acids 454-465 as the main binding site, which could be disrupted by mutation. A cell-permeable peptide corresponding to this region disrupted the PDE8A/Raf-1 interaction in cells, thereby reducing ERK activation and the cellular response to EGF. Overexpres-sion of a catalytically inactive PDE8A in cells displayed a dominant negative phenotype on ERK activation. These effects were recapitulated at the organism level in genetically modified (PDE8A-/-) mice. Similarly, PDE8 deletion in Drosophila melanogaster reduced basal ERK activation and sensitized flies to stress-induced death. We propose that PDE8A is a physiological regulator of Raf-1 signaling in some cells.

Original languageEnglish (US)
Pages (from-to)E1533-E1542
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number16
StatePublished - Apr 16 2013

ASJC Scopus subject areas

  • General


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