PKA:AKAP79:IQGAP1 complex dissociates to active PKA subunits in response to cAMP

Stable Identifier
Reaction [transition]
Homo sapiens
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The inactive Protein Kinase A (PKA) complex contains 2 regulatory subunits and 2 catalytic subunits. Binding of the regulatory subunits to the catalytic subunits maintains inactivity. In humans there are 3 different catalytic subunits and 4 different regulatory subunits. The particular subunits present in the beta cells of the pancreas are unknown. In beta cells PKA is associated with AKAP79 and IQGAP1, which are believed to tether PKA to the inner surface of the plasma membrane.
Activation by cAMP occurs when each regulatory subunit binds 2 molecules of cAMP, causing dissociation of the catalytic subunits. The active catalytic subunits are thereby released to phosphorylate their target proteins.
Prolonged exposure to increased cAMP levels results in translocation of the active catalytic subunits to the nucleus, where they regulate the PDX-1 and CREB transcription factors and cause increased transcription of the insulin gene.
Literature References
PubMed ID Title Journal Year
15569269 Glucagon-like peptide-1: regulation of insulin secretion and therapeutic potential

Brock, B, Gromada, J, Rorsman, P, Schmitz, O

Basic Clin Pharmacol Toxicol 2004
12938160 Identification of an IQGAP1/AKAP79 complex in beta-cells

Lester, LB, Rigas, JD, Nauert, JB

J Cell Biochem 2003
12180908 Protein kinase A translocation and insulin secretion in pancreatic beta-cells: studies with adenylate cyclase toxin from Bordetella pertussis

Trucco, MM, Wolf, BA, Greene, SR, Matschinsky, FM, Young, RA, Gao, Z, Hewlett, EL

Biochem J 2002
17306374 Mechanisms of action of glucagon-like peptide 1 in the pancreas

Egan, JM, Doyle, ME

Pharmacol Ther 2007
Catalyst Activity

cAMP binding activity of PKA:AKAP79:IQGAP1 Complex [plasma membrane]

Inferred From
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