Evidence for involvement of A-kinase anchoring protein in activation of rat arterial K(ATP) channels by protein kinase A.
1. We have investigated the possible role of A-kinase anchoring proteins (AKAPs) in protein kinase A (PKA) signalling to ATP-sensitive K+ (K(ATP)) channels of rat isolated mesenteric arterial smooth muscle cells using whole-cell patch clamp and peptides that inhibit PKA-AKAP binding. 2. Intracellular Ht31 peptide (20 microM), which inhibits the PKA-AKAP interaction, blocked K(ATP) current activation by either dibutyryl cAMP or calcitonin gene-related peptide. Ht31-proline (20 microM), which does not inhibit PKA binding to AKAP, did not block K(ATP) current activation. 3. Ht31 reduced K(ATP) current activated by pinacidil and also prevented its inhibition by Rp-cAMPS, effects consistent with Ht31 blocking steady-state K(ATP) channel activation by PKA. However, Ht31 did not prevent K(ATP) current activation by the catalytic subunit of PKA. 4. An 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 K(ATP) channels by PKA involve the localization of PKA by an AKAP.
Hayabuchi
Y
Y
Department of Cell Physiology and Pharmacology, University of Leicester, PO Box 138, Leicester LE1 9HN, UK.
Dart
C
C
Standen
N B
NB
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D054754:Cyclic AMP-Dependent Protein Kinase RIIalpha Subunit; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology; D008297:Male; D008638:Mesenteric Arteries / Q000166:cytology; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000201:enzymology*; D018408:Patch-Clamp Techniques; D010446:Peptide Fragments / Q000494:pharmacology; D015221:Potassium Channels / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D002352:Carrier Proteins; D054754:Cyclic AMP-Dependent Protein Kinase RIIalpha Subunit; D010446:Peptide Fragments; D015221:Potassium Channels; C517822:Prkar2a protein, rat; D003994:Bucladesine; D000255:Adenosine Triphosphate; D017868:Cyclic AMP-Dependent Protein Kinases; D015740:Calcitonin Gene-Related Peptide