Research in my laboratory addresses how nerve and muscle cells form the synaptic membranes that enable them to communicate. During development, the area of the muscle cell contacted by the arriving nerve terminal undergoes a dramatic transformation, changing from relatively unspecialized sarcoganizes these receptors into clusters is likely to involve other proteins located in the postsynaptic complex. We have been studying these proteins at neuromuscular synapses forming in amphibian nerve-muscle co-cultures. One of our current objectives is to identify proteins that are concentrated in the postsynaptic membrane before or during the clustering of AChR. This problem is addressed using fluorescence labeling techniques coupled with digital and confocal microscopy methods. The results will identify postsynaptic proteins that may play a role in anchoring AChR. A second objective is to determine the spatial relationship between postsynaptic proteins, using immunoelectron labeling techniques coupled with rotary replication methods. These experiments will identify proteins that are situated in close enough proximity to AChR that they may undergo direct molecular interactions with the receptors. This information will help clarify how postsynaptic proteins anchor AChR, and how they contribute to the organization of the postsynaptic complex.
Luther, P.W., Samuelsson, S.J., Pumplin, D.W., and Bloch, R.J., "Clustered acetylcholine receptors have two levels of organization in Xenopus muscle cells", Cell Motil. Cytoskel. 28:179-193, 1994.
Luther, P.W., Samuelsson, S.J., Pumplin, D.W. and Bloch, R.J. (1996). Cytoskeletal-membrane interactions at the postsynaptic density of Xenopus neuromuscular junctions. J. Neurocytol. 25:417-427.