This project is an outgrowth of work in this laboratory using ultrastructural methods and immunocytochemistry to study cytoplasmic proteins associated with the postsynaptic membrane of Torpedo electric tissue. The main long-term goal has been, and remains, to identify the mechanisms by which accumulations (""""""""clusters"""""""") of acetylcholine receptor molecules are stabilized (""""""""anchored"""""""") against lateral diffusion in the plasma membrane. In this proposal, the underlying idea--that anchoring is mediated by cytoskeletal and other cytoplasmic structures--is expanded to include a role for cluster-specific basal lamina, and the work is shifted to skeletal muscle from rat and Xenopus laevis. The previous methods plus freeze-fracture/deep-etch electron microscopy will be applied to clusters on muscle cells in culture, developing neuromuscular junctions, and the mature junction. Cytoskeletal, other cytoplasmic, and extracellular proteins at clusters will be identified immunocytochemically and localized relative to the receptor, the structures in which these proteins occur will be visualized in 3-dimensions, and how identified proteins fit into these structures will be determined. It is hoped that by judicious choices of sample and with the aid of cell biological manipulation of clusters, the various roles of these structures in receptor anchoring, in maintenance of the cell-cell contact nature of the junction, and in other possible synaptic activities can be delineated.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS015293-10
Application #
3396094
Study Section
Neurological Sciences Subcommittee 1 (NLS)
Project Start
1979-04-01
Project End
1991-03-31
Budget Start
1989-07-01
Budget End
1991-03-31
Support Year
10
Fiscal Year
1989
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Type
Schools of Medicine
DUNS #
078861598
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Kramarcy, N R; Vidal, A; Froehner, S C et al. (1994) Association of utrophin and multiple dystrophin short forms with the mammalian M(r) 58,000 dystrophin-associated protein (syntrophin). J Biol Chem 269:2870-6
Peters, M F; Kramarcy, N R; Sealock, R et al. (1994) beta 2-Syntrophin: localization at the neuromuscular junction in skeletal muscle. Neuroreport 5:1577-80
Butler, M H; Douville, K; Murnane, A A et al. (1992) Association of the Mr 58,000 postsynaptic protein of electric tissue with Torpedo dystrophin and the Mr 87,000 postsynaptic protein. J Biol Chem 267:6213-8
Hamilton, E H; Sealock, R; Wallace, N R et al. (1992) Trichohyalin: purification from porcine tongue epithelium and characterization of the native protein. J Invest Dermatol 98:881-9
Lai, F A; Liu, Q Y; Xu, L et al. (1992) Amphibian ryanodine receptor isoforms are related to those of mammalian skeletal or cardiac muscle. Am J Physiol 263:C365-72
Turner, C E; Kramarcy, N; Sealock, R et al. (1991) Localization of paxillin, a focal adhesion protein, to smooth muscle dense plaques, and the myotendinous and neuromuscular junctions of skeletal muscle. Exp Cell Res 192:651-5
Sealock, R; Butler, M H; Kramarcy, N R et al. (1991) Localization of dystrophin relative to acetylcholine receptor domains in electric tissue and adult and cultured skeletal muscle. J Cell Biol 113:1133-44
Kramarcy, N R; Sealock, R (1991) Commercial preparations of colloidal gold-antibody complexes frequently contain free active antibody. J Histochem Cytochem 39:37-9
Kramarcy, N R; Sealock, R (1990) Dystrophin as a focal adhesion protein. Collocalization with talin and the Mr 48,000 sarcolemmal protein in cultured Xenopus muscle. FEBS Lett 274:171-4
Chen, Q; Sealock, R; Peng, H B (1990) A protein homologous to the Torpedo postsynaptic 58K protein is present at the myotendinous junction. J Cell Biol 110:2061-71

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