Evidence for involvement of A-kinase anchoring protein in activation of rat arterial KATP channels by protein kinase A

Authors

  • Y. Hayabuchi,

    1. Department of Cell Physiology and Pharmacology, University of Leicester, PO Box 138, Leicester LE1 9HN, UK
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  • C. Dart,

    1. Department of Cell Physiology and Pharmacology, University of Leicester, PO Box 138, Leicester LE1 9HN, UK
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  • N. B. Standen

    Corresponding author
    1. Department of Cell Physiology and Pharmacology, University of Leicester, PO Box 138, Leicester LE1 9HN, UK
    • Corresponding author
      N. B. Standen: Department of Cell Physiology and Pharmacology, University of Leicester, PO Box 138, Leicester LE1 9HN, UK. Email: nbs@le.ac.uk

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Abstract

  • 1We have investigated the possible role of A-kinase anchoring proteins (AKAPs) in protein kinase A (PKA) signalling to ATP-sensitive K+ (KATP) channels of rat isolated mesenteric arterial smooth muscle cells using whole-cell patch clamp and peptides that inhibit PKA-AKAP binding.
  • 2Intracellular Ht31 peptide (20 μm), which inhibits the PKA-AKAP interaction, blocked KATP current activation by either dibutyryl cAMP or calcitonin gene-related peptide. Ht31-proline (20 μm), which does not inhibit PKA binding to AKAP, did not block KATP current activation.
  • 3Ht31 reduced KATP current activated by pinacidil and also prevented its inhibition by Rp-cAMPS, effects consistent with Ht31 blocking steady-state KATP channel activation by PKA. However, Ht31 did not prevent KATP current activation by the catalytic subunit of PKA.
  • 4An antibody to the RII subunit of PKA showed localization of PKA near to the cell membrane. Our results provide evidence that both steady-state and receptor-driven activation of KATP channels by PKA involve the localization of PKA by an AKAP.

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