Abstract
cAMP-dependent protein kinase is anchored to discrete cellular compartments by a family of proteins, the A-kinase anchor proteins (AKAPs). We have investigated in vivo and in vitro the biological effects of the expression of a prototypic member of the family, AKAP75, on smooth muscle cells. In vitro expression of AKAP75 in smooth muscle cells stimulated cAMP-induced transcription, increased the levels of the cyclin-dependent kinase-2 inhibitor p27(kip1), and reduced cell proliferation. In vivo expression of exogenous AKAP75 in common carotid arteries, subjected to balloon injury, significantly increased the levels of p27(kip1) and inhibited neointimal hyperplasia. Both the effects in smooth muscle cells in vitro and in carotid arteries in vivo were specifically dependent on the amplification of cAMP-dependent protein kinase (PKA) signals by membrane-bound PKA, as indicated by selective loss of the AKAP75 biological effects in mutants defective in the PKA anchor domain or by suppression of AKAP effects by the PKA-specific protein kinase inhibitor. These data indicate that AKAP proteins selectively amplify cAMP-PKA signaling in vitro and in vivo and suggest a possible target for the inhibition of the neointimal hyperplasia after vascular injury.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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8-Bromo Cyclic Adenosine Monophosphate / pharmacology
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A Kinase Anchor Proteins
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Adaptor Proteins, Signal Transducing*
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Animals
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Carotid Arteries / chemistry
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Carotid Arteries / pathology
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Carrier Proteins / genetics
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Carrier Proteins / metabolism*
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Cell Cycle Proteins*
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Cell Division / drug effects
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Cell Division / physiology*
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Cells, Cultured
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Chloramphenicol O-Acetyltransferase / drug effects
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Chloramphenicol O-Acetyltransferase / genetics
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Chloramphenicol O-Acetyltransferase / metabolism
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Cyclic AMP-Dependent Protein Kinases / drug effects
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Cyclic AMP-Dependent Protein Kinases / metabolism*
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Cyclin-Dependent Kinase Inhibitor p27
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DNA / biosynthesis
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DNA / drug effects
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DNA, Recombinant
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Gene Transfer Techniques
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Immunohistochemistry
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Microtubule-Associated Proteins / analysis
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Muscle, Smooth, Vascular / cytology
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Muscle, Smooth, Vascular / drug effects
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Muscle, Smooth, Vascular / metabolism*
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Plasmids / genetics
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Rats
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Rats, Wistar
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Recombinant Fusion Proteins / drug effects
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Signal Transduction / drug effects
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Time Factors
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Tumor Suppressor Proteins*
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Tunica Intima / chemistry
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Tunica Intima / pathology
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Tunica Media / chemistry
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Tunica Media / pathology
Substances
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A Kinase Anchor Proteins
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Adaptor Proteins, Signal Transducing
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Akap5 protein, rat
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Carrier Proteins
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Cdkn1b protein, rat
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Cell Cycle Proteins
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DNA, Recombinant
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Microtubule-Associated Proteins
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Recombinant Fusion Proteins
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Tumor Suppressor Proteins
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Cyclin-Dependent Kinase Inhibitor p27
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8-Bromo Cyclic Adenosine Monophosphate
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DNA
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Chloramphenicol O-Acetyltransferase
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Cyclic AMP-Dependent Protein Kinases