The goal of this proposal is to study the dynamics (the removal, the insertion, and the mobility) of the extracellular matrix acetylcholinesterase (ACHE) in the synaptic cleft in the neuromuscular junction (NMJ) of living mice. In particular, we will study what factors that might regulate its dynamic behavior. We will focus on the role of synaptic activity, a key molecule in the extracellular basal lamina (laminin alpha 4) and in postsynaptic proteins, and the dystrophin glycoprotein complex. Our second goal is to investigate whether the metabolic stability of acetylcholine receptors (AChR) in the postsynaptic membrane is influenced by AChE function. Finally we will study changes in synaptic dynamics of both AChE and AChR at a single synapse. To address these questions we will use the NMJ as a model of synapses in vivo. The use of high-resolution confocal microscopy, in vivo fluorescence imaging assay and the photo-unbinding technique that we developed recently will help us to better understand how the densities of AChE and AChR are maintained and regulated in living synapses. By investigating such questions, we should gain a better understanding of how synaptic alterations occur in less accessible central synapses. Additionally many neuromuscular diseases have either primarily or secondarily major impact on the density of AChRs and AChEs at neuromuscular junctions such as myasthenia gravis. By understanding the regulation of these key synaptic molecules, we expect to define new approaches that might be used to develop effective therapies for these devastating diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS047332-04
Application #
7082119
Study Section
Special Emphasis Panel (ZRG1-MDCN-1 (01))
Program Officer
Porter, John D
Project Start
2003-09-30
Project End
2008-09-29
Budget Start
2006-07-01
Budget End
2008-09-29
Support Year
4
Fiscal Year
2006
Total Cost
$269,047
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
073133571
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Aittaleb, Mohamed; Martinez-Pena Y Valenzuela, Isabel; Akaaboune, Mohammed (2017) Spatial distribution and molecular dynamics of dystrophin glycoprotein components at the neuromuscular junction in vivo. J Cell Sci 130:1752-1759
Chen, Po-Ju; Martinez-Pena Y Valenzuela, Isabel; Aittaleb, Mohamed et al. (2016) AChRs Are Essential for the Targeting of Rapsyn to the Postsynaptic Membrane of NMJs in Living Mice. J Neurosci 36:5680-5
Aittaleb, Mohamed; Chen, Po-Ju; Akaaboune, Mohammed (2015) Failure of lysosome clustering and positioning in the juxtanuclear region in cells deficient in rapsyn. J Cell Sci 128:3744-56
Basu, Sreya; Sladecek, Stefan; Martinez de la Peña y Valenzuela, Isabel et al. (2015) CLASP2-dependent microtubule capture at the neuromuscular junction membrane requires LL5? and actin for focal delivery of acetylcholine receptor vesicles. Mol Biol Cell 26:938-51
Brenner, Hans Rudolf; Akaaboune, Mohammed (2014) Recycling of acetylcholine receptors at ectopic postsynaptic clusters induced by exogenous agrin in living rats. Dev Biol 394:122-8
Martinez-Pena y Valenzuela, Isabel; Pires-Oliveira, Marcelo; Akaaboune, Mohammed (2013) PKC and PKA regulate AChR dynamics at the neuromuscular junction of living mice. PLoS One 8:e81311
Mouslim, Chakib; Aittaleb, Mohamed; Hume, Richard I et al. (2012) A role for the calmodulin kinase II-related anchoring protein (?kap) in maintaining the stability of nicotinic acetylcholine receptors. J Neurosci 32:5177-85
Martinez-Pena y Valenzuela, Isabel; Mouslim, Chakib; Pires-Oliveira, Marcelo et al. (2011) Nicotinic acetylcholine receptor stability at the NMJ deficient in ?-syntrophin in vivo. J Neurosci 31:15586-96
Martinez-Pena y Valenzuela, Isabel; Mouslim, Chakib; Akaaboune, Mohammed (2010) Calcium/calmodulin kinase II-dependent acetylcholine receptor cycling at the mammalian neuromuscular junction in vivo. J Neurosci 30:12455-65
Bruneau, Emile G; Akaaboune, Mohammed (2010) Dynamics of the rapsyn scaffolding protein at the neuromuscular junction of live mice. J Neurosci 30:614-9

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