In this project, the applicant will investigate the regulation of Na+/Ca2+ exchange activity in transfected Chinese hamster ovary cells that permanently express either the wild-type cardiac Na+/Ca2+ exchanger or mutant exchangers created by site-directed mutagenesis. The cental hypothesis is that exchange activity in intact cells is regulated at three different levels of complexity: (1) throughkinetic alterations induced by changes in cytosolic (Ca2+), (2) through interactions with the cytoskeleton, and (3) through interactions with Ca2+ sequestering organelles. The applicant will characterize the regulation of exchange activity by cytosolic (Na+), (Ca2+), and pH by measuring exchange-mediated Ba2+ influx in cells treated with the ionophores gramicidin and ionomycin. The applicant will also examine the influence of exchange activity of cytoskeletal changes induced by the phosphatase inhibitor calyculin A, and by osmotic shrinkage, with special emphasis on the role of intermediate filaments in the response. Finally, the applicant will use selective inhibitors and Ca2+ leading/depletion protocols to examine the role of Ca2+ uptake and release by the endoplasmic reticulum and otehr Ca2+ sequestering organelles in activating or deactivating exchange activity.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
2R01HL049932-05
Application #
2028876
Study Section
Cardiovascular and Pulmonary Research A Study Section (CVA)
Project Start
1993-06-01
Project End
2001-05-31
Budget Start
1997-06-01
Budget End
1998-05-31
Support Year
5
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Medicine & Dentistry of NJ
Department
Pharmacology
Type
Schools of Medicine
DUNS #
605799469
City
Newark
State
NJ
Country
United States
Zip Code
07107
Condrescu, Madalina; Reeves, John P (2010) Inhibition of sodium-calcium exchange by KB-R7943: Dodecylamine and sphingosine in transfected Chinese hamster ovary cells. Cell Calcium 47:404-11
Turner, Jay D; Thomas, Andrew P; Reeves, John P et al. (2009) Calcineurin activation by slow calcium release from intracellular stores suppresses protein kinase C regulation of L-type calcium channels in L6 cells. Cell Calcium 46:242-7
Chernysh, Olga; Condrescu, Madalina; Reeves, John P (2008) Sodium-dependent inactivation of sodium/calcium exchange in transfected Chinese hamster ovary cells. Am J Physiol Cell Physiol 295:C872-82
Reeves, John P; Abdellatif, Maha; Condrescu, Madalina (2008) The sodium-calcium exchanger is a mechanosensitive transporter. J Physiol 586:1549-63
Babich, Olga; Reeves, John; Shirokov, Roman (2007) Block of CaV1.2 channels by Gd3+ reveals preopening transitions in the selectivity filter. J Gen Physiol 129:461-75
Urbanczyk, Jason; Chernysh, Olga; Condrescu, Madalina et al. (2006) Sodium-calcium exchange does not require allosteric calcium activation at high cytosolic sodium concentrations. J Physiol 575:693-705
Condrescu, Madalina; Reeves, John P (2006) Actin-dependent regulation of the cardiac Na(+)/Ca(2+) exchanger. Am J Physiol Cell Physiol 290:C691-701
Hantash, Basil M; Thomas, Andrew P; Reeves, John P (2006) Regulation of the cardiac L-type calcium channel in L6 cells by arginine-vasopressin. Biochem J 400:411-9
Le, Hoa Dinh; Omelchenko, Alexander; Hryshko, Larry V et al. (2005) Allosteric activation of sodium-calcium exchange by picomolar concentrations of cadmium. J Physiol 563:105-17
Chernysh, Olga; Condrescu, Madalina; Reeves, John P (2004) Calcium-dependent regulation of calcium efflux by the cardiac sodium/calcium exchanger. Am J Physiol Cell Physiol 287:C797-806

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