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Targeting of type I protein kinase A to lipid rafts is required for platelet inhibition by the 3′,5′-cyclic adenosine monophosphate-signaling pathway

Naseem, K. M.; Raslan, Z.; Magwenzi, S.; Aburima, A.; Taskén, K.; Naseem, K. M.

Authors

K. M. Naseem

Z. Raslan

S. Magwenzi

A. Aburima

K. Taskén

K. M. Naseem

Abstract

Background Platelet adhesion to von Willebrand factor (VWF) is modulated by 3′,5′-cyclic adenosine monophosphate (cAMP) signaling through protein kinase A (PKA)-mediated phosphorylation of glycoprotein (GP)Ibβ. A-kinase anchoring proteins (AKAPs) are proposed to control the localization and substrate specificity of individual PKA isoforms. However, the role of PKA isoforms in regulating the phosphorylation of GPIbβ and platelet response to VWF is unknown. Objectives We wished to determine the role of PKA isoforms in the phosphorylation of GPIbβ and platelet activation by VWF as a model for exploring the selective partitioning of cAMP signaling in platelets. Results The two isoforms of PKA in platelets, type I (PKA-I) and type II (PKA-II), were differentially localized, with a small pool of PKA-I found in lipid rafts. Using a combination of Far Western blotting, immunoprecipitation, proximity ligation assay and cAMP pull-down we identified moesin as an AKAP that potentially localizes PKA-I to rafts. Introduction of cell-permeable anchoring disruptor peptide, RI anchoring disruptor (RIAD-Arg₁₁), to block PKA-I/AKAP interactions, uncoupled PKA-RI from moesin, displaced PKA-RI from rafts and reduced kinase activity in rafts. Examination of GPIbβ demonstrated that it was phosphorylated in response to low concentrations of PGI2 in a PKA-dependent manner and occurred primarily in lipid raft fractions. RIAD-Arg₁₁ caused a significant reduction in raft-localized phosphoGPIbβ and diminished the ability of PGI₂ to regulate VWF-mediated aggregation and thrombus formation in vitro. Conclusion We propose that PKA-I-specific AKAPs in platelets, including moesin, organize a selective localization of PKA-I required for phosphorylation of GPIbβ and contribute to inhibition of platelet VWF interactions.

Journal Article Type Article
Publication Date Sep 1, 2015
Journal Journal of thrombosis and haemostasis
Print ISSN 1538-7933
Electronic ISSN 1538-7836
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 13
Issue 9
Pages 1721-1734
Institution Citation Raslan, Z., Magwenzi, S., Aburima, A., Taskén, K., & Naseem, K. M. (2015). Targeting of type I protein kinase A to lipid rafts is required for platelet inhibition by the 3′,5′-cyclic adenosine monophosphate-signaling pathway. Journal of thrombosis and haemostasis : JTH, 13(9), 1721-1734. doi:10.1111/jth.13042
DOI https://doi.org/10.1111/jth.13042
Keywords A-kinase anchor proteins, Blood platelets, Cyclic AMP, Lycoprotein Ib-IX complex, Signal transduction
Publisher URL http://onlinelibrary.wiley.com/doi/10.1111/jth.13042/abstract
Copyright Statement ©2016 University of Hull
Additional Information Authors' accepted manuscript of article published in: Journal of thrombosis and haemostasis, 2015, v.13, issue 9

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