Disruption of Protein Kinase A Localization Using a Trans-activator of Transcription (TAT)-conjugated A-kinase-anchoring Peptide Reduces Cardiac Function *

摘要: Localization of protein kinase A (PKA) via A-kinase-anchoring proteins (AKAPs) is important for cAMP responsiveness in many cellular systems, and evidence suggests that AKAPs play an role cardiac signaling. To test the importance AKAP-mediated targeting PKA on function, we designed a cell-permeable peptide, which termed trans-activator transcription (TAT)-AKAD TAT-conjugated disruptor, using binding region AKAP10 tested effects this peptide isolated myocytes Langendorff-perfused mouse hearts. We initially validated TAT-AKAD as localization inhibitor by use confocal microscopy fractionation to show treatment with disrupts type I II regulatory subunits. Knockdown activity was demonstrated decrease phosphorylation phospholamban troponin after β-adrenergic stimulation myocytes. Treatment reduced myocyte shortening rates contraction relaxation. Injection (1 μm), but not scrambled control into coronary circulation perfused hearts rapidly (<1 min) reversibly decreased heart rate peak left ventricular developed pressure. also had pronounced effect pressure (−dP/dt), consistent delayed relaxation heart. The contractility persisted pretreated isoproterenol. Disruption thus negative chronotropy, inotropy, lusitropy, thereby indicating key AKAP-targeted contractile function.