Postsynaptic Rapsyn Dynamics at the Neuromuscular Junction of Living Animals

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

The efficiency of nerve impulse transmission to muscle cells depends on the number and density of acetylcholine receptor proteins on the muscle membrane. These receptors are localized to specialized structures known as synapses, characterized by folds in the postsynaptic membrane. Receptors are firmly held in the crest of the folds by a host of specialized scaffold proteins. The goal of this study is to investigate the dynamics of one critical component of this scaffold, rapsyn, when levels of synaptic activity are manipulated. To address the dynamics of rapsyn at the synapse, the PI will fuse jellyfish green fluorescent protein (GFP) to rapsyn and introduce the construct into the neck of the mouse (sternomastoid muscle). This makes it possible to monitor and image a particular synapse over the course of several days in the living animal. Receptor proteins will be labeled by fluorescent bungarotoxin, a snake venom that binds with high affinity to the receptor. The PI will investigate the following questions: first, what is the lifetime of rapsyn at individual synapse in vivo. Second what is the effect of rapsyn overexpression on the metabolic stability of receptors in vivo. Finally, the PI will investigate the effect of synaptic activity on the dynamics of rapsyn at individual synapses in vivo. The PI will promote the training of graduate, undergraduate and high school students, including those of underrepresented groups. The PI has extensive experience in training undergraduate students. In addition this proposal will enhance teaching performance and learning in the areas of neuroscience. Results will be disseminated to the scientific community through publications and by presenting findings in meetings. Finally the PI's lab will be involved in outreach to the community.