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

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

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.

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. https://doi.org/10.1111/jth.13042

• Journal Article Type: Article
• Acceptance Date: Jun 18, 2015
• Online Publication Date: Aug 12, 2015
• Publication Date: Sep 1, 2015
• Deposit Date: Dec 16, 2015
• Publicly Available Date: Nov 23, 2017
• Journal: Journal of thrombosis and haemostasis
• Print ISSN: 1538-7933
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 13
• Issue: 9
• Pages: 1721-1734
• DOI: https://doi.org/10.1111/jth.13042
• Keywords: A-kinase anchor proteins, Blood platelets, Cyclic AMP, Lycoprotein Ib-IX complex, Signal transduction
• Public URL: https://hull-repository.worktribe.com/output/382863
• Publisher URL: http://onlinelibrary.wiley.com/doi/10.1111/jth.13042/abstract
• Additional Information: Authors' accepted manuscript of article published in: Journal of thrombosis and haemostasis, 2015, v.13, issue 9
• Contract Date: Nov 23, 2017