An increasing body of experimental evidence points to a crucial role for nucleoside diphosphate kinase (NDP kinase) in the development, differentiation and growth of cells. Alterations in NDP kinase expression or activity are correlated with malignancy and metastasis, and can be lethal in the early stages of development. In atrial cells, intracellular application of antibodies to NDP kinase impairs activation of potassium channels (K-Ach)) by agonist-bound muscarinic cholinergic receptors via the G protein Gk, implicating this enzyme in the regulation of transmembrane signalling in heart. The overall aim of this proposal is to understand the molecular mechanisms by which NDP kinase contributes to signal transduction pathways that underlie the physiological response of cardiac cells to neurotransmitters. The basic experimental system chosen is the isolated. adult atrial myocyte, which provides a unique opportunity to study NDP kinase function in vivo, at the cellular and molecular levels. The approach proposed involves patch clamp recording of receptormodulated ionic currents, combined with intracellular injection of purified enzyme and specific antibodies. With these tools, we hope to be able to dissect the contribution of NDP kinase to the early events resulting from stimulation of beta-adrenergic and muscarinic receptors, as reflected by changes in muscarinic K+ currents and calcium currents. Complementary biochemical and immunochemical techniques will also be applied in order to clarify the molecular aspects of these processes. Muscarinic and beta-adrenergic receptors affect profoundly myocardial excitability and contractility, and modulate other important physiological responses as well. Therefore, elucidation of the essential features of NDP kinase participation in signal transduction may be relevant to the understanding of the pathophysiology of chronic and acute processes where myocardial function is compromised.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL048726-02
Application #
3367868
Study Section
Cardiovascular and Pulmonary Research A Study Section (CVA)
Project Start
1992-08-01
Project End
1996-07-31
Budget Start
1993-08-01
Budget End
1994-07-31
Support Year
2
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of Virginia
Department
Type
Schools of Medicine
DUNS #
001910777
City
Charlottesville
State
VA
Country
United States
Zip Code
22904
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Otero, A S; Xu, L; Ni, Y et al. (1998) Receptor-independent activation of atrial muscarinic potassium channels in the absence of nucleotides. J Biol Chem 273:28868-72
Otero, A S (1997) Copurification of vimentin, energy metabolism enzymes, and a MER5 homolog with nucleoside diphosphate kinase. Identification of tissue-specific interactions. J Biol Chem 272:14690-4
Yi, X B; Seitzer, N M; de S Otero, A (1996) Neutralizing antibodies to nucleoside diphosphate kinase inhibit the enzyme in vitro and in vivo: evidence for two distinct mechanisms of activation of atrial currents by ATPgammaS. Biochim Biophys Acta 1310:334-42
Xu, L; Murphy, J; Otero, A S (1996) Participation of nucleoside-diphosphate kinase in muscarinic K+ channel activation does not involve GTP formation. J Biol Chem 271:21120-5
Lee, M S; Sawyer, S; Arnush, M et al. (1996) Transforming growth factor-beta fails to inhibit allograft rejection or virus-induced autoimmune diabetes in transgenic mice. Transplantation 61:1112-5
Lee, M S; Gu, D; Feng, L et al. (1995) Accumulation of extracellular matrix and developmental dysregulation in the pancreas by transgenic production of transforming growth factor-beta 1. Am J Pathol 147:42-52
Otero, A S; Yi, X B; Gray, M C et al. (1995) Membrane depolarization prevents cell invasion by Bordetella pertussis adenylate cyclase toxin. J Biol Chem 270:9695-7
Otero, A de S; Sweitzer, N M (1993) Benzoquinoid tyrosine kinase inhibitors are potent blockers of cardiac muscarinic receptor function. Mol Pharmacol 44:595-604