AKAP79/150 interacts with AC8 and regulates Ca2+-dependent cAMP synthesis in pancreatic and neuronal systems

J Biol Chem. 2010 Jun 25;285(26):20328-42. doi: 10.1074/jbc.M110.120725. Epub 2010 Apr 21.

Abstract

Protein kinase A anchoring proteins (AKAPs) provide the backbone for targeted multimolecular signaling complexes that serve to localize the activities of cAMP. Evidence is accumulating of direct associations between AKAPs and specific adenylyl cyclase (AC) isoforms to facilitate the actions of protein kinase A on cAMP production. It happens that some of the AC isoforms (AC1 and AC5/6) that bind specific AKAPs are regulated by submicromolar shifts in intracellular Ca(2+). However, whether AKAPs play a role in the control of AC activity by Ca(2+) is unknown. Using a combination of co-immunoprecipitation and high resolution live cell imaging techniques, we reveal an association of the Ca(2+)-stimulable AC8 with AKAP79/150 that limits the sensitivity of AC8 to intracellular Ca(2+) events. This functional interaction between AKAP79/150 and AC8 was observed in HEK293 cells overexpressing the two signaling molecules. Similar findings were made in pancreatic insulin-secreting cells and cultured hippocampal neurons that endogenously express AKAP79/150 and AC8, which suggests important physiological implications for this protein-protein interaction with respect to Ca(2+)-stimulated cAMP production.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A Kinase Anchor Proteins / genetics
  • A Kinase Anchor Proteins / metabolism*
  • Adenylyl Cyclases / genetics
  • Adenylyl Cyclases / metabolism*
  • Animals
  • Animals, Newborn
  • Blotting, Western
  • Calcium / metabolism*
  • Calcium / pharmacology
  • Cell Line
  • Cell Line, Tumor
  • Cells, Cultured
  • Cyclic AMP / biosynthesis*
  • Enzyme Activation / drug effects
  • Fluorescence Resonance Energy Transfer
  • Humans
  • Immunoprecipitation
  • Insulin-Secreting Cells / metabolism*
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Neurons / cytology
  • Neurons / metabolism*
  • Protein Binding
  • RNA Interference
  • Rats
  • Rats, Wistar
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Transfection

Substances

  • A Kinase Anchor Proteins
  • AKAP5 protein, human
  • Luminescent Proteins
  • Recombinant Fusion Proteins
  • Cyclic AMP
  • Adenylyl Cyclases
  • adenylyl cyclase 8
  • Calcium