Abstract

The myofilaments of cardiac and skeletal cells are critically dependent on the intracellular concentration of Ca2+ for regulation of their contractile activity, In turn, the intracellular concentration of Ca2+ is controlled by membrane structures which are endowed with specific transport systems for the divalent cation. It is the aim of this proposal to combine ultrastructural, biochemical and physiological methods of investigation on order to clarify the mechanisms of Ca2+ uptake and release by these membranes. The proposed research will be carried out with a range of experimental systems including dissociated cells, isolated sarcoplasmic reticulum vesicles, solubilized and purified proteins (Ca2+ ATPase) and reconstituted membranes. Specific ultrastructural and/or conformational features of these systems will be related to functional activities with specific reference to active Ca2+ transport and coupled enzyme activity. Sequential steps of the enzyme cycle will be studied by rapid mixing techniques in the forward and reverse directions, leading to active transport and ATP synthesis respectively. Passive Ca2+ fluxes will be also studied, and their relevance to contractile regulation will be evaluated by monitoring sarcomere activation in dissociated cell preparations. Comparative studies will be performed under the influence of pharmacological agents. These studies will lead to clarification of basic biological mechanisms: ion transport, energy transduction and contractile control.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
5P01HL027867-04
Application #
3097989
Study Section
Heart, Lung, and Blood Research Review Committee A (HLBA)
Project Start
1982-09-01
Project End
1987-08-31
Budget Start
1985-09-01
Budget End
1986-08-31
Support Year
4
Fiscal Year
1985
Total Cost
Indirect Cost

  Institution

Name
University of Maryland Baltimore
Department
Type
Schools of Medicine
DUNS #
003255213
City
Baltimore
State
MD
Country
United States
Zip Code
21201

  Publications

Mahoney Jr, William M; Hong, Jeong-Ho; Yaffe, Michael B et al. (2005) The transcriptional co-activator TAZ interacts differentially with transcriptional enhancer factor-1 (TEF-1) family members. Biochem J 388:217-25
Toyoshima, Chikashi; Inesi, Giuseppe (2004) Structural basis of ion pumping by Ca2+-ATPase of the sarcoplasmic reticulum. Annu Rev Biochem 73:269-92
Ma, Hailun; Inesi, Giuseppe; Toyoshima, Chikashi (2003) Substrate-induced conformational fit and headpiece closure in the Ca2+ATPase (SERCA). J Biol Chem 278:28938-43
McLean, B Gail; Lee, Katherine S; Simpson, Paul C et al. (2003) Basal and alpha1-adrenergic-induced activity of minimal rat betaMHC promoters in cardiac myocytes requires multiple TEF-1 but not NFAT binding sites. J Mol Cell Cardiol 35:461-71
Sumbilla, Carlota; Lewis, David; Hammerschmidt, Tina et al. (2002) The slippage of the Ca2+ pump and its control by anions and curcumin in skeletal and cardiac sarcoplasmic reticulum. J Biol Chem 277:13900-6
Long, X; Wu, G; Gaa, S T et al. (2002) Inhibition of protein phosphatase-1 is linked to phosphorylation of p53 and apoptosis. Apoptosis 7:31-9
Hua, Suming; Inesi, Giuseppe; Nomura, Hiromi et al. (2002) Fe(2+)-catalyzed oxidation and cleavage of sarcoplasmic reticulum ATPase reveals Mg(2+) and Mg(2+)-ATP sites. Biochemistry 41:11405-10
Maeda, Tomoji; Mazzulli, Joseph R; Farrance, Iain K G et al. (2002) Mouse DTEF-1 (ETFR-1, TEF-5) is a transcriptional activator in alpha 1-adrenergic agonist-stimulated cardiac myocytes. J Biol Chem 277:24346-52
Inesi, Giuseppe; Zhang, Zhongsen; Lewis, David (2002) Cooperative setting for long-range linkage of Ca(2+) binding and ATP synthesis in the Ca(2+) ATPase. Biophys J 83:2327-32
Hua, Suming; Ma, Hailun; Lewis, David et al. (2002) Functional role of ""N"" (nucleotide) and ""P"" (phosphorylation) domain interactions in the sarcoplasmic reticulum (SERCA) ATPase. Biochemistry 41:2264-72

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