Adenylyl cyclase type VI increases Akt activity and phospholamban phosphorylation in cardiac myocytes

J Biol Chem. 2008 Nov 28;283(48):33527-35. doi: 10.1074/jbc.M805825200. Epub 2008 Oct 5.

Abstract

Increased expression of adenylyl cyclase VI has beneficial effects on the heart, but strategies that increase cAMP production in cardiac myocytes usually are harmful. Might adenylyl cyclase VI have beneficial effects unrelated to increased beta-adrenergic receptor-mediated signaling? We previously reported that adenylyl cyclase VI reduces cardiac phospholamban expression. Our focus in the current studies is how adenylyl cyclase VI influences phospholamban phosphorylation. In cultured cardiac myocytes, increased expression of adenylyl cyclase VI activates Akt by phosphorylation at serine 473 and threonine 308 and is associated with increased nuclear phospho-Akt. Activated Akt phosphorylates phospholamban, a process that does not require beta-adrenergic receptor stimulation or protein kinase A activation. These previously unrecognized signaling events would be predicted to promote calcium handling and increase contractile function of the intact heart independently of beta-adrenergic receptor activation. We speculate that phospholamban phosphorylation, through activation of Akt, may be an important mechanism by which adenylyl cyclase VI increases the function of the failing heart.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adenylyl Cyclases / genetics
  • Adenylyl Cyclases / metabolism*
  • Animals
  • Calcium Signaling / genetics
  • Calcium-Binding Proteins / genetics
  • Calcium-Binding Proteins / metabolism*
  • Cell Nucleus / enzymology
  • Cell Nucleus / genetics
  • Cells, Cultured
  • Cyclic AMP / genetics
  • Cyclic AMP / metabolism
  • Cyclic AMP-Dependent Protein Kinases / genetics
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Enzyme Activation / genetics
  • Gene Expression Regulation, Enzymologic* / genetics
  • Heart Failure / enzymology
  • Heart Failure / genetics
  • Mice
  • Myocardium / enzymology*
  • Myocytes, Cardiac / enzymology*
  • Phosphorylation / genetics
  • Proto-Oncogene Proteins c-akt / genetics
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Rats
  • Receptors, Adrenergic, beta / genetics
  • Receptors, Adrenergic, beta / metabolism

Substances

  • Calcium-Binding Proteins
  • Receptors, Adrenergic, beta
  • phospholamban
  • Cyclic AMP
  • Proto-Oncogene Proteins c-akt
  • Cyclic AMP-Dependent Protein Kinases
  • Adenylyl Cyclases
  • adenylyl cyclase 6