Abstract

Cardiac glycoside-elicited inotropy is known to be due to inhibition of the Na,K-ATPase. This laboratory discovered the existence of Na,K-ATPase isoforms in the brain, and that they had markedly different affinities for cardiac glycosides in some species. In the first period of support, monoclonal antibodies were produced that permitted identification of three Na,K-ATPase isoforms in the heart. The monoclonal antibody epitopes were mapped; used to determine specificity; and used to study transmembrane protein topography. They then were used to assess factors that control the expression of the isoforms in the rat heart. Changes were seen during development, hypothyroidism, and hypertension that are important for understanding the heart's physiological sensitivity to the drug. The objective now is to use monoclonal antibody epitope mapping to investigate the structure of the Na,K-ATPase isoforms. Antibodies will aid the biochemical analysis of isoform variants. They will be used to determine the topography of transmembrane segments in the controversial C-terminal half. They will also be used to deduce the location of the ouabain binding site. Such physical evidence complements and tests models supported by molecular biology; for example, we have evidence that the ouabain binding site is not located at the position indicated by site-directed mutagenesis.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL036271-07
Application #
3351132
Study Section
Physical Biochemistry Study Section (PB)
Project Start
1987-07-01
Project End
1997-06-30
Budget Start
1993-07-01
Budget End
1994-06-30
Support Year
7
Fiscal Year
1993
Total Cost
Indirect Cost

  Institution

Name
Massachusetts General Hospital
Department
Type
DUNS #
City
Boston
State
MA
Country
United States
Zip Code
02199

  Publications

Arystarkhova, Elena; Sweadner, Kathleen J (2016) Functional Studies of Na(+),K(+)-ATPase Using Transfected Cell Cultures. Methods Mol Biol 1377:321-32
Sweadner, Kathleen J (2016) Colorimetric Assays of Na,K-ATPase. Methods Mol Biol 1377:89-104
Arystarkhova, Elena; Liu, Yi B; Salazar, Cynthia et al. (2013) Hyperplasia of pancreatic beta cells and improved glucose tolerance in mice deficient in the FXYD2 subunit of Na,K-ATPase. J Biol Chem 288:7077-85
Sweadner, Kathleen J; Pascoa, Jennifer L; Salazar, Cynthia A et al. (2011) Post-transcriptional control of Na,K-ATPase activity and cell growth by a splice variant of FXYD2 protein with modified mRNA. J Biol Chem 286:18290-300
Arystarkhova, Elena; Donnet, Claudia; Munoz-Matta, Ana et al. (2007) Multiplicity of expression of FXYD proteins in mammalian cells: dynamic exchange of phospholemman and gamma-subunit in response to stress. Am J Physiol Cell Physiol 292:C1179-91
Jia, Li-Guo; Donnet, Claudia; Bogaev, Roberta C et al. (2005) Hypertrophy, increased ejection fraction, and reduced Na-K-ATPase activity in phospholemman-deficient mice. Am J Physiol Heart Circ Physiol 288:H1982-8
Arystarkhova, Elena; Sweadner, Kathleen J (2005) Splice variants of the gamma subunit (FXYD2) and their significance in regulation of the Na, K-ATPase in kidney. J Bioenerg Biomembr 37:381-6
Jones, D Holstead; Li, Tony Y; Arystarkhova, Elena et al. (2005) Na,K-ATPase from mice lacking the gamma subunit (FXYD2) exhibits altered Na+ affinity and decreased thermal stability. J Biol Chem 280:19003-11
Sweadner, Kathleen J (2005) Phospholemman: a new force in cardiac contractility. Circ Res 97:510-1
Wetzel, Randall K; Pascoa, Jennifer L; Arystarkhova, Elena (2004) Stress-induced expression of the gamma subunit (FXYD2) modulates Na,K-ATPase activity and cell growth. J Biol Chem 279:41750-7

Showing the most recent 10 out of 39 publications