description): The overall goal of this proposal is to elucidate the basis for structural organization of the calcium release units (CRUs) of cardiac and skeletal muscle which underlie excitation-contraction coupling. CRUs are comprised of junctional sarcoplasmic reticulum (jSR) which are composed of a luminal calcium-binding protein, calsequestrin (CSQ), and several membrane proteins which include the calcium-release channel (ryanodine receptor; RyRs), and supporting proteins junctin and triadin. The adjacent areas of sarcolemma include L-type calcium channels (dihydropyridine receptors; DHPRs). To determine the basis for the assembly, organization, and maintenance of structural integrity of these units, structure will be assessed by electron microscopy, using thin sections and freeze fracture methods, and protein composition will be assessed using immunofluorescence coupled to confocal microscopy and by Western blotting. Three strategies will be used to assess the effect of altered protein composition on the structure of CRUs. 1) Transgenic mice which overexpress one or more of the CRU proteins will be studied. 2) Muscle specific CRU proteins will be expressed in non-muscle cells in order to determine the proteins necessary for formation of CRUs. 3) The composition of CRUs in skeletal muscle of Amphioxus will be examined using molecular biology and ultrastructural approaches.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL048093-08
Application #
6389206
Study Section
Cardiovascular and Pulmonary Research A Study Section (CVA)
Program Officer
Reinlib, Leslie
Project Start
1993-07-01
Project End
2003-06-30
Budget Start
2001-07-01
Budget End
2002-06-30
Support Year
8
Fiscal Year
2001
Total Cost
$215,000
Indirect Cost
Name
University of Pennsylvania
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
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Park, Chang Sik; Chen, Shan; Lee, Hoyong et al. (2013) Targeted ablation of the histidine-rich Ca(2+)-binding protein (HRC) gene is associated with abnormal SR Ca(2+)-cycling and severe pathology under pressure-overload stress. Basic Res Cardiol 108:344
Huang, Xiaohu; Sun, Lei; Ji, Shuangxi et al. (2013) Kissing and nanotunneling mediate intermitochondrial communication in the heart. Proc Natl Acad Sci U S A 110:2846-51

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