| Content Provider |
World Health Organization (WHO)-Global Index Medicus |
| Author |
Springer, Tzvia I. Kuster, Diederik W. D. Finley, Natosha L. Sadayappan, Sakthivel Martin, Jody L. Govindan, Suresh |
| Spatial Coverage |
Asia |
| Description |
Author Affiliation: Kuster DW ( From the Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois 60153, and.); Govindan S ( From the Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois 60153, and.); Springer TI ( the Department of Microbiology and.); Martin JL ( From the Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois 60153, and.); Finley NL ( the Department of Microbiology and the Cell, Molecular, and Structural Biology Program, Miami University, Oxford, Ohio 45056.); Sadayappan S ( From the Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois 60153, and ssadayappan@luc.edu.) |
| Abstract |
Hypertrophic cardiomyopathy (HCM) results from mutations in genes encoding sarcomeric proteins, most often MYBPC3, which encodes cardiac myosin binding protein-C (cMyBP-C). A recently discovered HCM-associated 25-base pair deletion in MYBPC3 is inherited in millions worldwide. Although this mutation causes changes in the C10 domain of cMyBP-C (cMyBP-C(C10mut)), which binds to the light meromyosin (LMM) region of the myosin heavy chain, the underlying molecular mechanism causing HCM is unknown. In this study, adenoviral expression of cMyBP-C(C10mut) in cultured adult rat cardiomyocytes was used to investigate protein localization and evaluate contractile function and Ca(2+) transients, compared with wild-type cMyBP-C expression (cMyBP-C(WT)) and controls. Forty-eight hours after infection, 44% of cMyBP-C(WT) and 36% of cMyBP-C(C10mut) protein levels were determined in total lysates, confirming equal expression. Immunofluorescence experiments showed little or no localization of cMyBP-C(C10mut) to the C-zone, whereas cMyBP-C(WT) mostly showed C-zone staining, suggesting that cMyBP-C(C10mut) could not properly integrate in the C-zone of the sarcomere. Subcellular fractionation confirmed that most cMyBP-C(C10mut) resided in the soluble fraction, with reduced presence in the myofilament fraction. Also, cMyBP-C(C10mut) displayed significantly reduced fractional shortening, sarcomere shortening, and relaxation velocities, apparently caused by defects in sarcomere function, because Ca(2+) transients were unaffected. Co-sedimentation and protein cross-linking assays confirmed that C10(mut) causes the loss of C10 domain interaction with myosin LMM. Protein homology modeling studies showed significant structural perturbation in cMyBP-C(C10mut), providing a potential structural basis for the alteration in its mode of interaction with myosin LMM. Therefore, expression of cMyBP-C(C10mut) protein is sufficient to cause contractile dysfunction in vitro. |
| ISSN |
00219258 |
| e-ISSN |
1083351X |
| Journal |
Journal of Biological Chemistry |
| Issue Number |
9 |
| Volume Number |
290 |
| Language |
English |
| Publisher |
American Society for Biochemistry and Molecular Biology (United States) |
| Publisher Date |
2015-02-27 |
| Publisher Place |
United States |
| Access Restriction |
Open |
| Subject Keyword |
Cardiomyopathy, Hypertrophic Genetics Carrier Proteins Genetic Predisposition To Disease Mutation Myocytes, Cardiac Metabolism Animals Asian Continental Ancestry Group Ethnology Physiopathology Chemistry Cell Size Cells, Cultured Immunoblotting Microscopy, Fluorescence Models, Molecular Muscle Contraction Cytology Myosin Subfragments Protein Binding Protein Structure, Tertiary Rats, Sprague-Dawley Sarcomeres Subcellular Fractions Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't Biochemistry Molecular Biology |
| Content Type |
Text |
| Resource Type |
Article |
| Subject |
Cell Biology Biochemistry Molecular Biology |
