Targeted overexpression of phospholamban to mouse atrium depresses Ca2+ transport and contractility

Joachim Neumann, Peter Boknik, Anna De Paoli-Roach, Loren Field, Howard A. Rockman, Yvonne M. Kobayashi, Jeffrey S. Kelley, Larry Jones

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Phospholamban is a small phosphoprotein regulator of the Ca2+-pump of cardiac sarcoplasmic reticulum. Dephosphorylated phospholamban inhibits the Ca2+-pump and depresses contractility, whereas phosphorylation of phospholamban by cAMP-activated mechanisms relieves this inhibition and increases contractility. In order to better understand the function of phospholamban in living systems, a transgenic mouse model was established employing targeted overexpression of phospholamban to the atrium, which normally expresses low levels of the protein. Overexpression was achieved by fusing the α-MHC-promoter or the ANF-promoter to the phospholamban gene. Double transgenic mice were created by mating mice positive for each transgene. In single transgenic lineages, phospholamban was overexpressed four to six-fold in left atrium. In the double transgenic mice, phospholamban was overexpressed eight- to nine-fold. In the three transgenic strains. Ca2+ uptake by the sarcoplasmic reticulum was depressed to 22-30% of control values at low ionized calcium. This depression of Ca2+ uptake was largely reversed by addition of a phospholamban monoclonal antibody. In the atrial muscle strips, the time course of contraction was increased in a concentration-dependent manner by overexpression of phospholamban, whereas the basal developed tension was decreased up to 85% by phospholamban-overexpression. In all transgenic lineages, isoproterenol, a β-adrenoceptor agonist, reversed the depression of contractility caused by overexpression of phospholamban and significantly shortened time parameters to levels approaching control values. These data demonstrate that overexpression of phospholamban in a mammalian myocardial tissue normally deficient in the protein substantially inhibits basal contractility, and furthermore suggest that in myocardial tissues containing high levels of the protein, phosphorylation of phospholamban can account for many of the positive inotropic and lusitropic effects of β-adrenergic stimulation.

Original languageEnglish
Pages (from-to)1991-2002
Number of pages12
JournalJournal of Molecular and Cellular Cardiology
Volume30
Issue number10
DOIs
StatePublished - Oct 1998

Fingerprint

Transgenic Mice
Sarcoplasmic Reticulum
phospholamban
Phosphorylation
Proteins
Phosphoproteins
Atrial Natriuretic Factor
Heart Atria
Transgenes
Isoproterenol
Adrenergic Agents
Adrenergic Receptors
Monoclonal Antibodies
Calcium
Muscles
Genes

Keywords

  • Ca uptake
  • Contractility
  • Phospholamban
  • Transgenic mice

ASJC Scopus subject areas

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

Cite this

Targeted overexpression of phospholamban to mouse atrium depresses Ca2+ transport and contractility. / Neumann, Joachim; Boknik, Peter; De Paoli-Roach, Anna; Field, Loren; Rockman, Howard A.; Kobayashi, Yvonne M.; Kelley, Jeffrey S.; Jones, Larry.

In: Journal of Molecular and Cellular Cardiology, Vol. 30, No. 10, 10.1998, p. 1991-2002.

Research output: Contribution to journalArticle

Neumann, Joachim ; Boknik, Peter ; De Paoli-Roach, Anna ; Field, Loren ; Rockman, Howard A. ; Kobayashi, Yvonne M. ; Kelley, Jeffrey S. ; Jones, Larry. / Targeted overexpression of phospholamban to mouse atrium depresses Ca2+ transport and contractility. In: Journal of Molecular and Cellular Cardiology. 1998 ; Vol. 30, No. 10. pp. 1991-2002.
@article{9764040f69d340c693919cfba8c265b5,
title = "Targeted overexpression of phospholamban to mouse atrium depresses Ca2+ transport and contractility",
abstract = "Phospholamban is a small phosphoprotein regulator of the Ca2+-pump of cardiac sarcoplasmic reticulum. Dephosphorylated phospholamban inhibits the Ca2+-pump and depresses contractility, whereas phosphorylation of phospholamban by cAMP-activated mechanisms relieves this inhibition and increases contractility. In order to better understand the function of phospholamban in living systems, a transgenic mouse model was established employing targeted overexpression of phospholamban to the atrium, which normally expresses low levels of the protein. Overexpression was achieved by fusing the α-MHC-promoter or the ANF-promoter to the phospholamban gene. Double transgenic mice were created by mating mice positive for each transgene. In single transgenic lineages, phospholamban was overexpressed four to six-fold in left atrium. In the double transgenic mice, phospholamban was overexpressed eight- to nine-fold. In the three transgenic strains. Ca2+ uptake by the sarcoplasmic reticulum was depressed to 22-30{\%} of control values at low ionized calcium. This depression of Ca2+ uptake was largely reversed by addition of a phospholamban monoclonal antibody. In the atrial muscle strips, the time course of contraction was increased in a concentration-dependent manner by overexpression of phospholamban, whereas the basal developed tension was decreased up to 85{\%} by phospholamban-overexpression. In all transgenic lineages, isoproterenol, a β-adrenoceptor agonist, reversed the depression of contractility caused by overexpression of phospholamban and significantly shortened time parameters to levels approaching control values. These data demonstrate that overexpression of phospholamban in a mammalian myocardial tissue normally deficient in the protein substantially inhibits basal contractility, and furthermore suggest that in myocardial tissues containing high levels of the protein, phosphorylation of phospholamban can account for many of the positive inotropic and lusitropic effects of β-adrenergic stimulation.",
keywords = "Ca uptake, Contractility, Phospholamban, Transgenic mice",
author = "Joachim Neumann and Peter Boknik and {De Paoli-Roach}, Anna and Loren Field and Rockman, {Howard A.} and Kobayashi, {Yvonne M.} and Kelley, {Jeffrey S.} and Larry Jones",
year = "1998",
month = "10",
doi = "10.1006/jmcc.1998.0760",
language = "English",
volume = "30",
pages = "1991--2002",
journal = "Journal of Molecular and Cellular Cardiology",
issn = "0022-2828",
publisher = "Academic Press Inc.",
number = "10",

}

TY - JOUR

T1 - Targeted overexpression of phospholamban to mouse atrium depresses Ca2+ transport and contractility

AU - Neumann, Joachim

AU - Boknik, Peter

AU - De Paoli-Roach, Anna

AU - Field, Loren

AU - Rockman, Howard A.

AU - Kobayashi, Yvonne M.

AU - Kelley, Jeffrey S.

AU - Jones, Larry

PY - 1998/10

Y1 - 1998/10

N2 - Phospholamban is a small phosphoprotein regulator of the Ca2+-pump of cardiac sarcoplasmic reticulum. Dephosphorylated phospholamban inhibits the Ca2+-pump and depresses contractility, whereas phosphorylation of phospholamban by cAMP-activated mechanisms relieves this inhibition and increases contractility. In order to better understand the function of phospholamban in living systems, a transgenic mouse model was established employing targeted overexpression of phospholamban to the atrium, which normally expresses low levels of the protein. Overexpression was achieved by fusing the α-MHC-promoter or the ANF-promoter to the phospholamban gene. Double transgenic mice were created by mating mice positive for each transgene. In single transgenic lineages, phospholamban was overexpressed four to six-fold in left atrium. In the double transgenic mice, phospholamban was overexpressed eight- to nine-fold. In the three transgenic strains. Ca2+ uptake by the sarcoplasmic reticulum was depressed to 22-30% of control values at low ionized calcium. This depression of Ca2+ uptake was largely reversed by addition of a phospholamban monoclonal antibody. In the atrial muscle strips, the time course of contraction was increased in a concentration-dependent manner by overexpression of phospholamban, whereas the basal developed tension was decreased up to 85% by phospholamban-overexpression. In all transgenic lineages, isoproterenol, a β-adrenoceptor agonist, reversed the depression of contractility caused by overexpression of phospholamban and significantly shortened time parameters to levels approaching control values. These data demonstrate that overexpression of phospholamban in a mammalian myocardial tissue normally deficient in the protein substantially inhibits basal contractility, and furthermore suggest that in myocardial tissues containing high levels of the protein, phosphorylation of phospholamban can account for many of the positive inotropic and lusitropic effects of β-adrenergic stimulation.

AB - Phospholamban is a small phosphoprotein regulator of the Ca2+-pump of cardiac sarcoplasmic reticulum. Dephosphorylated phospholamban inhibits the Ca2+-pump and depresses contractility, whereas phosphorylation of phospholamban by cAMP-activated mechanisms relieves this inhibition and increases contractility. In order to better understand the function of phospholamban in living systems, a transgenic mouse model was established employing targeted overexpression of phospholamban to the atrium, which normally expresses low levels of the protein. Overexpression was achieved by fusing the α-MHC-promoter or the ANF-promoter to the phospholamban gene. Double transgenic mice were created by mating mice positive for each transgene. In single transgenic lineages, phospholamban was overexpressed four to six-fold in left atrium. In the double transgenic mice, phospholamban was overexpressed eight- to nine-fold. In the three transgenic strains. Ca2+ uptake by the sarcoplasmic reticulum was depressed to 22-30% of control values at low ionized calcium. This depression of Ca2+ uptake was largely reversed by addition of a phospholamban monoclonal antibody. In the atrial muscle strips, the time course of contraction was increased in a concentration-dependent manner by overexpression of phospholamban, whereas the basal developed tension was decreased up to 85% by phospholamban-overexpression. In all transgenic lineages, isoproterenol, a β-adrenoceptor agonist, reversed the depression of contractility caused by overexpression of phospholamban and significantly shortened time parameters to levels approaching control values. These data demonstrate that overexpression of phospholamban in a mammalian myocardial tissue normally deficient in the protein substantially inhibits basal contractility, and furthermore suggest that in myocardial tissues containing high levels of the protein, phosphorylation of phospholamban can account for many of the positive inotropic and lusitropic effects of β-adrenergic stimulation.

KW - Ca uptake

KW - Contractility

KW - Phospholamban

KW - Transgenic mice

UR - http://www.scopus.com/inward/record.url?scp=0032192291&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032192291&partnerID=8YFLogxK

U2 - 10.1006/jmcc.1998.0760

DO - 10.1006/jmcc.1998.0760

M3 - Article

C2 - 9799653

AN - SCOPUS:0032192291

VL - 30

SP - 1991

EP - 2002

JO - Journal of Molecular and Cellular Cardiology

JF - Journal of Molecular and Cellular Cardiology

SN - 0022-2828

IS - 10

ER -