title: Genetically Encoded Biosensors Reveal PKA Hyperphosphorylation on the Myofilaments in Rabbit Heart Failure.
abstract: BACKGROUND
  In heart failure, myofilament proteins display abnormal phosphorylation, which contributes to contractile dysfunction. The mechanisms underlying the dysregulation of protein phosphorylation on myofilaments is not clear.
  
  
  OBJECTIVE
  This study aims to understand the mechanisms underlying altered phosphorylation of myofilament proteins in heart failure.
  
  
  RESULTS
  We generate a novel genetically encoded protein kinase A (PKA) biosensor anchored onto the myofilaments in rabbit cardiac myocytes to examine PKA activity at the myofilaments in responses to adrenergic stimulation. We show that PKA activity is shifted from the sarcolemma to the myofilaments in hypertrophic failing rabbit myocytes. In particular, the increased PKA activity on the myofilaments is because of an enhanced β2 adrenergic receptor signal selectively directed to the myofilaments together with a reduced phosphodiesterase activity associated with the myofibrils. Mechanistically, the enhanced PKA activity on the myofilaments is associated with downregulation of caveolin-3 in the hypertrophic failing rabbit myocytes. Reintroduction of caveolin-3 in the failing myocytes is able to normalize the distribution of β2 adrenergic receptor signal by preventing PKA signal access to the myofilaments and to restore contractile response to adrenergic stimulation.
  
  
  CONCLUSIONS
  In hypertrophic rabbit myocytes, selectively enhanced β2 adrenergic receptor signaling toward the myofilaments contributes to elevated PKA activity and PKA phosphorylation of myofilament proteins. Reintroduction of caveolin-3 is able to confine β2 adrenergic receptor signaling and restore myocyte contractility in response to β adrenergic stimulation.
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: Federica
authors: F
authors: Barbagallo
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: Bing
authors: B
authors: Xu
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: Gopireddy R
authors: GR
authors: Reddy
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: Toni
authors: T
authors: West
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: Qingtong
authors: Q
authors: Wang
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: Qin
authors: Q
authors: Fu
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: Minghui
authors: M
authors: Li
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: Qian
authors: Q
authors: Shi
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: Kenneth S
authors: KS
authors: Ginsburg
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: William
authors: W
authors: Ferrier
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: Andrea M
authors: AM
authors: Isidori
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: Fabio
authors: F
authors: Naro
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: Hemal H
authors: HH
authors: Patel
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: Julie
authors: J
authors: Bossuyt
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.).
authors: Donald
authors: D
authors: Bers
authors: From the Department of Pharmacology, University of California at Davis (F.B., B.X., G.R.R., T.W., Q.W., Q.F., M.L., Q.S., K.S.G., J.B., D.B., Y.K.X.); Department of Experimental Medicine (F.B., A.M.I.) and Department of Anatomical, Histological, Forensic, and Orthopedic Sciences (F.N.), Sapienza University of Rome, Italy; Department of Medicine and Epidemiology, School of Veterinary Medicine, and Surgical Research Facility, School of Medicine, University of California, Davis (W.F.); VA San Diego Healthcare System, La Jolla, CA (H.H.P.); Department of Anesthesiology, University of California, San Diego, La Jolla (H.H.P.); and VA Northern California Healthcare System, Mather (Y.K.X.). ykxiang@ucdavis.edu.
authors: Yang K
authors: YK
authors: Xiang
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D006333:Heart Failure / Q000201:enzymology* / Q000235:genetics*; D032383:Myocytes, Cardiac / Q000201:enzymology; D009210:Myofibrils / Q000201:enzymology* / Q000235:genetics*; D010766:Phosphorylation / Q000502:physiology; D011817:Rabbits
chemical_list: D017868:Cyclic AMP-Dependent Protein Kinases
keywords: adrenergic receptor; heart failure; myofibrils; phosphorylation; protein kinase A