Journal article
Subcellular distribution of the 1,4-dihydropyridine receptor in rabbit skeletal muscle in situ: an immunofluorescence and immunocolloidal gold-labeling study
The Journal of cell biology, Vol.109(1), pp.135-147
07/1989
DOI: 10.1083/jcb.109.1.135
PMID: 2545725
Abstract
The subcellular distribution of the 1,4-dihydropyridine receptor was determined in rabbit skeletal muscle in situ by immunofluorescence and immunoelectron microscopy. Longitudinal and transverse cryosections (5-8 microns) of rabbit gracilis muscle were labeled with monoclonal antibodies specific against either the alpha 1-subunit (170,000-D polypeptide) or the beta-subunit (52,000-D polypeptide) of the 1,4-dihydropyridine receptor by immunofluorescence labeling. In longitudinal sections, specific labeling was present only near the interface between the A- and I-band regions of the sarcomeres. In transverse sections, specific labeling showed a hexagonal staining pattern within each myofiber however, the relative staining intensity of the type II (fast) fibers was judged to be three- to fourfold higher than that of the type I (slow) fibers. Specific immunofluorescence labeling of the sarcolemma was not observed in either longitudinal or transverse sections. These results are consistent with the idea that the alpha 1-subunit and the beta-subunit of the purified 1,4-dihydropyridine receptor are densely distributed in the transverse tubular membrane. Immunoelectron microscopical localization with a monoclonal antibody to the alpha 1-subunit of the 1,4-dihydropyridine receptor showed that the 1,4-dihydropyridine receptor is densely distributed in the transverse tubular membrane. Approximately half of these were distributed in close proximity to the junctional region between the transverse tubules and the terminal cisternae. Specific labeling was also present in discrete foci in the subsarcolemmal region of the myofibers. The size and the nonrandom distribution of these foci in the subsarcolemmal region support the possibility that they correspond to invaginations from the sarcolemma called caveolae. In conclusion, our results demonstrate that the 1,4-dihydropyridine receptor in skeletal muscle is localized to the transverse tubular membrane and discrete foci in the subsarcolemmal region, possibly caveolae but absent from the lateral portion of the sarcolemma.
Details
- Title: Subtitle
- Subcellular distribution of the 1,4-dihydropyridine receptor in rabbit skeletal muscle in situ: an immunofluorescence and immunocolloidal gold-labeling study
- Creators
- Annelise O Jorgensen - Department of Anatomy, University of Toronto, CanadaAmy C.-Y ShenWayne ArnoldAlbert T LeungKevin P Campbell
- Resource Type
- Journal article
- Publication Details
- The Journal of cell biology, Vol.109(1), pp.135-147
- Publisher
- United States
- DOI
- 10.1083/jcb.109.1.135
- PMID
- 2545725
- ISSN
- 0021-9525
- eISSN
- 1540-8140
- Grant note
- HL-37187 / NHLBI NIH HHS
- Language
- English
- Date published
- 07/1989
- Academic Unit
- Neurology; Molecular Physiology and Biophysics; Iowa Neuroscience Institute
- Record Identifier
- 9984068270602771
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