1. Adenylyl cyclase 6 is selectively regulated by protein kinase A phosphorylation in a region involved in Galphas stimulation
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Chen, Y., Harry, A., Li, J., Martine Smit, Bai, X., Magnusson, R., Pieroni, J. P., Weng, G., Iyengar, R., Biophotonics and Medical Imaging, Medicinal chemistry, and AIMMS
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Insecta ,Molecular Sequence Data ,Research Support, U.S. Gov't, P.H.S ,Sequence Homology ,Research Support ,P.H.S ,Cell Line ,GTP-Binding Proteins ,Journal Article ,Site-Directed ,Animals ,Humans ,Amino Acid Sequence ,Phosphorylation ,Non-U.S. Gov't ,Binding Sites ,Sequence Homology, Amino Acid ,Research Support, Non-U.S. Gov't ,Cell Membrane ,Cyclic AMP-Dependent Protein Kinases ,Isoenzymes ,enzymes and coenzymes (carbohydrates) ,Amino Acid ,Mutagenesis ,Mutagenesis, Site-Directed ,U.S. Gov't ,Adenylyl Cyclases ,Signal Transduction - Abstract
Receptors activate adenylyl cyclases through the Galphas subunit. Previous studies from our laboratory have shown in certain cell types that express adenylyl cyclase 6 (AC6), heterologous desensitization included reduction of the capability of adenylyl cyclases to be stimulated by Galphas. Here we further analyze protein kinase A (PKA) effects on adenylyl cyclases. PKA treatment of recombinant AC6 in insect cell membranes results in a selective loss of stimulation by high (>10 nM) concentrations of Galphas. Similar treatment of AC1 or AC2 did not affect Galphas stimulation. Conversion of Ser-674 in AC6 to an Ala blocks PKA phosphorylation and PKA-mediated loss of Galphas stimulation. A peptide encoding the region 660-682 of AC6 blocks stimulation of AC6 and AC2 by high concentrations of Galphas. Substitution of Ser-674 to Asp in the peptide renders the peptide ineffective, indicating that the region 660-682 of AC6 is involved in regulation of signal transfer from Galphas. This region contains a conserved motif present in most adenylyl cyclases; however, the PKA phosphorylation site is unique to members of the AC6 family. These observations suggest a mechanism of how isoform selective regulatory diversity can be obtained within conserved regions involved in signal communication.