Journal article
Dystrophin-Glycoprotein Complex and Laminin Colocalize to the Sarcolemma and Transverse Tubules of Cardiac Muscle
Circulation research, Vol.72(2), pp.349-360
02/1993
DOI: 10.1161/01.RES.72.2.349
PMID: 8418988
Abstract
The expression and subcellular distribution of the dystrophin-glycoprotein complex and laminin were examined in cardiac muscle by immunoblot and immunofluorescence analysis of rabbit and sheep papillary muscle. The five dystrophin-associated proteins (DAPs), 156-DAG, 59-DAP, 50-DAG, 43-DAG, and 35-DAG, were identified in rabbit ventricular muscle and found to codistribute with dystrophin in both papillary myofibers and Purkinje fibers. The DAPs and dystrophin codistributed not only in the free surface sarcolemma but also in interior regions of the myofibers where T tubules are present. Neither the DAPs nor dystrophin were detected in intercalated discs, a specialized region of cardiac sarcolemma where neighboring myocardial cells are physically joined by cell-cell junctions. Similarly, in bundles of Purkinje fibers, which lack T tubules, DAPs and dystrophin were also found to codistribute at the free surface sarcolemma but were not detected either in the region of surface sarcolemma closely apposed to a neighboring Purkinje fiber or in interior regions of these myofibers. Comparison between the distribution of the dystrophin-glycoprotein complex and laminin showed that laminin codistributes with the components of this complex in both papillary myofibers and Purkinje fibers. These results are consistent with previous findings demonstrating that the extracellularly exposed 156-DAG (dystroglycan) of the skeletal muscle dystrophin-glycoprotein complex binds laminin, a component of the basement membrane. Although we demonstrate that DAPs, dystrophin, and laminin colocalize to the sarcolemma in rabbit and sheep papillary myofibers as they do in skeletal myofibers, the most striking difference between the subcellular distribution of these proteins in cardiac and skeletal muscle is that the dystrophin-glycoprotein complex and laminin also localize to regions of the fibers where T tubules are distributed in cardiac but not in skeletal muscle. These results imply that the protein composition and thus possibly some functions of T tubules in cardiac muscle are distinct from those of skeletal muscle.
Details
- Title: Subtitle
- Dystrophin-Glycoprotein Complex and Laminin Colocalize to the Sarcolemma and Transverse Tubules of Cardiac Muscle
- Creators
- Rhea Klietsch - Department of Anatomy & Cell Biology (R.K., W.A., A.O.J.), University of Toronto, and the Howard Hughes Medical Institute (K.P.C.), Department of Physiology and Biophysics, University of Iowa College of Medicine, Iowa CityJames ErvastiWayne ArnoldKevin CampbellAnnelise Jorgensen
- Resource Type
- Journal article
- Publication Details
- Circulation research, Vol.72(2), pp.349-360
- DOI
- 10.1161/01.RES.72.2.349
- PMID
- 8418988
- NLM abbreviation
- Circ Res
- ISSN
- 0009-7330
- eISSN
- 1524-4571
- Publisher
- American Heart Association, Inc
- Language
- English
- Date published
- 02/1993
- Academic Unit
- Neurology; Molecular Physiology and Biophysics; Iowa Neuroscience Institute
- Record Identifier
- 9984068278202771
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