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

Brown, K.M. et al. (2013) Phosphodiesterase-8A binds to and regulates Raf-1 kinase. Proceedings of the National Academy of Sciences of the United States of America, 110(16), E1533-E1542. (doi:10.1073/pnas.1303004110)

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Publisher's URL: http://dx.doi.org/10.1073/pnas.1303004110

Abstract

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. Overexpression 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.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Baillie, Professor George and Houslay, Professor Miles and Huston, Dr Elaine and Kolch, Prof Walter and Christian, Dr Frank and Terhzaz, Dr Selim and Day, Dr Jonathan and Davies, Professor Shireen
Authors: Brown, K.M., Day, J.P., Huston, E., Zimmermann, B., Hampel, K., Christian, F., Romano, D., Terhzaz, S., Lee, L.C.Y., Willis, M.J., Morton, D.B., Beavo, J.A., Shimizu-Albergine, M., Davies, S.A., Kolch, W., Houslay, M.D., and Baillie, G.S.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
College of Medical Veterinary and Life Sciences > Institute of Neuroscience and Psychology
Journal Name:Proceedings of the National Academy of Sciences of the United States of America
Publisher:National Academy of Sciences
ISSN:0027-8424
ISSN (Online):1091-6490
Published Online:18 March 2013
Copyright Holders:Copyright © 2013 National Academy of Sciences
First Published:First published in Proceedings of the National Academy of Sciences of the United States of America
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
438301Phosphodiesterase-4 isoforms - intracellular targeting, regulation and potential therapeutic targetsMiles HouslayMedical Research Council (MRC)G0600765RI NEUROSCIENCE & PSYCHOLOGY