Interaction of heterotrimeric G13 protein with an A-kinase-anchoring protein 110 (AKAP110) mediates cAMP-independent PKA activation

Curr Biol. 2001 Oct 30;11(21):1686-90. doi: 10.1016/s0960-9822(01)00530-9.

Abstract

Heterotrimeric G proteins and protein kinase A (PKA) are two important transmitters that transfer signals from a wide variety of cell surface receptors to generate physiological responses. The established mechanism of PKA activation involves the activation of the Gs-cAMP pathway. Binding of cAMP to the regulatory subunit of PKA (rPKA) leads to a release and subsequent activation of a catalytic subunit of PKA (cPKA). Here, we report a novel mechanism of PKA stimulation that does not require cAMP. Using yeast two-hybrid screening, we found that the alpha subunit of G13 protein interacted with a member of the PKA-anchoring protein family, AKAP110. Using in vitro binding and coimmunoprecipitation assays, we have shown that only activated G alpha 13 binds to AKAP110, suggesting a potential role for AKAP110 as a G alpha subunit effector protein. Importantly, G alpha 13, AKAP110, rPKA, and cPKA can form a complex, as shown by coimmunoprecipitation. By characterizing the functional significance of the G alpha 13-AKAP110 interaction, we have found that G alpha 13 induced release of the cPKA from the AKAP110-rPKA complex, resulting in a cAMP-independent PKA activation. Finally, AKAP110 significantly potentiated G alpha 13-induced activation of PKA. Thus, AKAP110 provides a link between heterotrimeric G proteins and cAMP-independent activation of PKA.

Publication types

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

MeSH terms

  • A Kinase Anchor Proteins
  • Adaptor Proteins, Signal Transducing*
  • Carrier Proteins / metabolism*
  • Cells, Cultured
  • Cyclic AMP / metabolism
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • Enzyme Activation
  • GTP-Binding Protein alpha Subunits, G12-G13
  • Guanine Nucleotides / metabolism
  • Heterotrimeric GTP-Binding Proteins / metabolism*
  • Humans
  • Kidney / cytology
  • Male
  • Models, Biological
  • Protein Binding
  • Protein Subunits
  • Two-Hybrid System Techniques

Substances

  • A Kinase Anchor Proteins
  • AKAP3 protein, human
  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • Guanine Nucleotides
  • Protein Subunits
  • Cyclic AMP
  • Cyclic AMP-Dependent Protein Kinases
  • GTP-Binding Protein alpha Subunits, G12-G13
  • Heterotrimeric GTP-Binding Proteins