ZFIN ID: ZDB-PUB-080616-24
Conformational Changes of a Ca2+-Binding Domain of the Na+ -Ca2+ Exchanger Monitored by FRET in Transgenic Zebrafish Heart
Xie, Y., Ottolia, M., John, S., Chen, J.N., and Philipson, K.D.
Date: 2008
Source: American journal of physiology. Cell physiology   295(2): C388-C393 (Journal)
Registered Authors: Chen, Jau-Nian
Keywords: Ca2+-binding domain, sodium-calcium exchange, zebrafish, FRET
MeSH Terms:
  • Animals
  • Animals, Genetically Modified
  • Caffeine/pharmacology
  • Calcium Signaling/drug effects
  • Calcium Signaling/physiology
  • DNA, Antisense/genetics
  • Dogs
  • Embryo, Nonmammalian/physiology
  • Fluorescence Resonance Energy Transfer*
  • Heart/drug effects
  • Heart/physiology*
  • Isoproterenol/pharmacology
  • Myocardial Contraction/drug effects
  • Myocardial Contraction/physiology
  • Nifedipine/pharmacology
  • Ouabain/pharmacology
  • Peptide Fragments/genetics
  • Protein Conformation
  • Protein Structure, Tertiary/genetics
  • Sodium-Calcium Exchanger/chemistry
  • Sodium-Calcium Exchanger/physiology*
  • Troponin T/genetics
  • Zebrafish/genetics
  • Zebrafish/physiology*
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/physiology*
PubMed: 18550703 Full text @ Am. J. Physiol. Cell Physiol.
The Na(+) -Ca(2+) exchanger is the major Ca(2+) extrusion mechanism in cardiac myocytes. The activity of the cardiac Na(+)-Ca(2+) exchanger is dynamically regulated by intracellular Ca(2+). Previous studies indicate that Ca(2+) binding to a high-affinity Ca(2+)-binding domain (CBD1) in the large intracellular loop is involved in regulation. We generated transgenic zebrafish with cardiac-specific expression of CBD1 linked to YFP and CFP. Ca(2+)-binding to CBD1 induces conformational changes as detected by FRET. With this transgenic fish model, we were able to monitor conformational changes of the Ca(2+) regulatory domain of NCX in intact hearts. Treatment with the positive inotropic agents ouabain and isoproterenol increased both Ca(2+) transients and Ca(2+)-induced changes in FRET. The results indicate that Ca(2+) regulation of the Na(+)-Ca(2+) exchanger domain CBD1 changes with inotropic state. The transgenic fish models will be useful to further characterize the regulatory properties of the Na(+)-Ca(2+) exchanger in vivo. Key words: Ca2+-binding domain, sodium-calcium exchange, zebrafish, FRET.