Adenylyl Cyclase

links: Enzyme reference: 9-18-2021

Adenylyl (Adenylate) Cyclase #

Catalyzes conversion of ATP to cAMP + pyrophosphate: The closest thing you’ll get to reversibility is PDE, catalyzing cAMP back into AMP.

• Activated simply by the binding of Gα-GTP. AC is deactivated when the GTP is hydrolyzed from the α subunit’s intrisic GTPase.

• I, III, and VIII: also stimulated by Ca-Calmodulin.!

• V and VI: inhibited by Ca2+ in a calmodulin-independent manner.

• II, IV and IX: stimulated by Gα-GTP.

• I, V and VI are most clearly inhibited by Gi, while other isoforms show less dual regulation by the inhibitory G protein.

• Colocalization of protein kinase A with adenylyl cyclase enhances protein kinase A activity during induction of long-lasting long-term-potentiation.

  • Anchoring Protein Kinase A with adenylyl cyclase produces significantly greater PKA activity, and phosphorylation of both Protein Phosphatase Inhibitor-1 and GluR1 on S845, than when PKA is anchored apart from adenylyl cyclase… anchoring PKA near its source of cAMP is critical because inactivation by phosphodiesterase limits diffusion of cAMP.
  • experimentally rescuing the deficit in LTP produced by disruption of PKA anchoring using phosphodiesterase inhibitors
    • So wait, does PDE elicit anchoring of PKA to AC?