Identification of an intracellular postsynaptic antigen at the frog neuromuscular junction.
Open Access
- 1 September 1982
- journal article
- research article
- Published by Rockefeller University Press in The Journal of cell biology
- Vol. 94 (3) , 521-530
- https://doi.org/10.1083/jcb.94.3.521
Abstract
A layer of amorphous, electron-dense material is situated at the cytoplasmic surface of the postsynaptic membrane of vertebrate neuromuscular synapses. The function of this structure is not clear, but its location suggests that it may have an important role in the formation and/or maintenance of the synapse. A monoclonal antibody raised against antigens from Torpedo electric organ binds to an intracellular, postsynaptic protein at the frog neuromuscular synapse. Indirect immunofluorescence on frozen sections of frog muscle was used to demonstrate that the antigen is concentrated at synaptic sites in normal muscle. In denervated muscle, the antigen remains concentrated at synaptic sites, but is also present at extrasynaptic regions of denervated myofibers. The antigen cannot be labeled in intact, whole muscle, but only in whole muscle that has been permeabilized with nonionic detergents. The antibody staining pattern in Triton X-100-permeabilized whole-mounts of the frog neuromuscular synapse is arranged in elongate, arborized areas which are characteristic of the frog neuromuscular synapse. The stained areas are striated and the striations occur with a periodicity that corresponds to the regular folding of the postsynaptic membrane. Immunoferritin labeling of fixed, saponin-permeabilized muscle demonstrates that the antigen is associated with amorphous material that is situated between the postsynaptic membrane and an underlying layer of intermediate filaments. The antigen, solubilized from Torpedo electric organ by high ionic strength, was identified by antibody binding to nitrocellulose replicas of SDS [sodium dodecyl sulfate] gels of Torpedo tissue. In Torpedo tissue, the antibody binds to a single protein band at 51,000 daltons (51 kd). The 51-kd protein shares an antigenic determinant with intermediate filament proteins, since a monoclonal antibody to all intermediate filaments reacts with the same 51-kd protein. The monoclonal antibody also reacts with a 55-kd protein in frog skin which is localized to the perinuclear region of the epithelial cells.This publication has 41 references indexed in Scilit:
- Cytoplasmic actin in postsynaptic structures at the neuromuscular junction.The Journal of cell biology, 1981
- An antiactin antibody that distinguishes between cytoplasmic and skeletal muscle actins.The Journal of cell biology, 1980
- Regulation of acetylcholinesterase appearance at neuromuscular junctions in vitroNature, 1980
- The characterization of actin associated with postsynaptic membranes from TorpedocalifornicaBiochemical and Biophysical Research Communications, 1980
- Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications.Proceedings of the National Academy of Sciences, 1979
- Isolation of pure IgG1, IgG2a and IgG2b immunoglobulins from mouse serum using protein A-SepharoseImmunochemistry, 1978
- Structural studies of a membrane-bound acetylcholine receptor from Torpedo californicaJournal of Molecular Biology, 1977
- Precision of reinnervation of original postsynaptic sites in frog muscle after a nerve crushJournal of Neurocytology, 1976
- Synaptic membrane structure inTorpedo electric organJournal of Neurocytology, 1975
- Fractionation and partial characterization of membrane particles from Torpedo californica electroplaxBiochemistry, 1973