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Functional differences between cardiac and renal isoforms of the rat Na+-Ca2+ exchanger NCX1 expressed in Xenopus oocytes.
- Source :
-
The Journal of physiology [J Physiol] 2000 Dec 15; Vol. 529 Pt 3, pp. 599-610. - Publication Year :
- 2000
-
Abstract
- The transcript of the Na+-Ca2+ exchanger gene NCX1 undergoes alternative splicing to produce tissue-specific isoforms. The cloned NCX1 isoforms were expressed in Xenopus oocytes and studied using a two-electrode voltage clamp method to measure Na+-Ca2+ exchanger activity. The cardiac isoform (NCX1.1) expressed in oocytes was less sensitive to depolarizing voltages and to activation by [Ca2+]i than the renal isoform (NCX1.3). The cardiac isoform of NCX1 is more sensitive to activation by protein kinase A (PKA) than the renal isoform which may be explained by preferential phosphorylation. The cardiac isoform of NCX1 is phosphorylated to a greater extent than the renal isoform. The action of PKA phosphorylation which increases the activity of the cardiac isoform of the Na+-Ca2+ exchanger in oocytes was confirmed in adult rat ventricular cardiomyocytes by measuring Na+-dependent Ca2+ flux. We conclude that alternative splicing of NCX1 confers distinct functional characteristics to tissue-specific isoforms of the Na+-Ca2+ exchanger.
- Subjects :
- Animals
Cyclic AMP-Dependent Protein Kinases metabolism
Electric Conductivity
Enzyme Activation physiology
Oocytes metabolism
Patch-Clamp Techniques
Phosphorylation
Protein Isoforms metabolism
Rats
Sodium-Calcium Exchanger physiology
Xenopus
Kidney metabolism
Myocardium metabolism
Sodium-Calcium Exchanger metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0022-3751
- Volume :
- 529 Pt 3
- Database :
- MEDLINE
- Journal :
- The Journal of physiology
- Publication Type :
- Academic Journal
- Accession number :
- 11118492
- Full Text :
- https://doi.org/10.1111/j.1469-7793.2000.00599.x