AKAP79 interacts with multiple adenylyl cyclase (AC) isoforms and scaffolds AC5 and -6 to alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptors.
Spatiotemporal specificity of cAMP action is best explained by targeting protein kinase A (PKA) to its substrates by A-kinase-anchoring proteins (AKAPs). At synapses in the brain, AKAP79/150 incorporates PKA and other regulatory enzymes into signal transduction networks that include beta-adrenergic receptors, alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA), and N-methyl-d-aspartic acid receptors. We previously showed that AKAP79/150 clusters PKA with type 5 adenylyl cyclase (AC5) to assemble a negative feedback loop in which the anchored kinase phosphorylates AC5 to dynamically suppress cAMP synthesis. We now show that AKAP79 can associate with multiple AC isoforms. The N-terminal regions of AC5, -6, and -9 mediate this protein-protein interaction. Mapping studies located a reciprocal binding surface between residues 77-108 of AKAP79. Intensity- and lifetime-based fluorescence resonance energy transfer demonstrated that deletion of AKAP79(77-108) region abolished AC5-AKAP79 interaction in living cells. The addition of the AKAP79(77-153) polypeptide fragment uncouples AC5/6 interactions with the anchoring protein and prevents PKA-mediated inhibition of AC activity in membranes. Use of the AKAP79(77-153) polypeptide fragment in brain extracts from wild-type and AKAP150(-/-) mice reveals that loss of the anchoring protein results in decreased AMPA receptor-associated AC activity. Thus, we propose that AKAP79/150 mediates protein-protein interactions that place AC5 in proximity to synaptic AMPA receptors.
Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas 77030, USA.
Riad
R
Efendiev
Bret K
BK
Samelson
Bao T
BT
Nguyen
Prasad V
PV
Phatarpekar
Faiza
F
Baameur
John D
JD
Scott
Carmen W
CW
Dessauer
D054758:A Kinase Anchor Proteins / Q000378:metabolism*; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D006624:Hippocampus / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D007527:Isoenzymes / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D051379:Mice; D009474:Neurons / Q000378:metabolism*; D018091:Receptors, AMPA / Q000378:metabolism*
D054758:A Kinase Anchor Proteins; D007527:Isoenzymes; D018091:Receptors, AMPA; D000262:Adenylyl Cyclases; C121100:adenylyl cyclase 6; C419510:adenylyl cyclase type V