Adenylyl cyclase 6 is selectively regulated by protein kinase A phosphorylation in a region involved in Galphas stimulation.
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.
Chen
Y
Y
Department of Pharmacology, Mount Sinai School of Medicine, New York, NY 10029, USA.
Harry
A
A
Li
J
J
Smit
M J
MJ
Bai
X
X
Magnusson
R
R
Pieroni
J P
JP
Weng
G
G
Iyengar
R
R
D000262:Adenylyl Cyclases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D007313:Insecta; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
D007527:Isoenzymes; D017868:Cyclic AMP-Dependent Protein Kinases; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases