HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 282, Issue 13, 9932-9940, March 30, 2007

This Article Full Text Full Text (PDF) All Versions of this Article: 282/13/9932    most recent M608714200v2 M608714200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bruneau, E. Articles by Akaaboune, M. Search for Related Content PubMed PubMed Citation Articles by Bruneau, E. Articles by Akaaboune, M. Social Bookmarking                      What's this?

The Dynamics of the Rapsyn Scaffolding Protein at Individual Acetylcholine Receptor Clusters^*

From the Department of Molecular, Cellular and Developmental Biology and Program in Neuroscience, University of Michigan, Ann Arbor, Michigan 48109

Rapsyn, a cytoplasmic receptor-associated protein, is required for the clustering of acetylcholine receptors (AChRs). Although AChR dynamics have been extensively studied, little is known about the dynamics of rapsyn. Here, we used a rapsyn-green fluorescent protein (GFP) fusion protein and quantitative fluorescent imaging to study the dynamics of rapsyn in transfected C2C12 myotubes. First, we found that rapsyn-GFP expression at clusters did not alter AChR aggregation, function, or turnover. Quantification of rapsyn immunofluorescence indicated that the expression of rapsyn-GFP proteins at clusters does not increase the overall rapsyn density compared with untransfected myotube clusters. Using time lapse imaging and fluorescence recovery after photobleaching, we demonstrated that the recovery of rapsyn-GFP fluorescence at clusters was very fast, with a halftime of about 1.5 h (3 times faster than AChRs). Inhibition of protein kinase C significantly altered receptor insertion, but it had no effect on rapsyn insertion. When cells were treated with the broad spectrum kinase inhibitor staurosporine, receptor insertion was decreased even further. However, inhibition of protein kinase A had no effect on insertion of either rapsyn or receptors. Finally, when cells were treated with neural agrin, rapsyn and AChRs were both directed away from preexisting clusters and accumulated together in new small clusters. These results demonstrate the remarkable dynamism of rapsyn, which may underlie the stability and maintenance of the postsynaptic scaffold and suggest that the insertion of different postsynaptic proteins may be operating independently.

Received for publication, September 10, 2006 , and in revised form, January 19, 2007.

^* This work was supported by the University of Michigan and NINDS, National Institutes of Health, Grants NS047332 (to M. A.) and NS056748 (to E. G. B.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

¹ To whom correspondence should be addressed: Dept. of Molecular, Cellular and Developmental Biology, 830 N. University Ave., Ann Arbor, MI 48109. Tel.: 734-647-8512; Fax: 734-647-0884; E-mail: makaabou{at}umich.edu.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				S. Nam, K. Min, H. Hwang, H.-o. Lee, J. H. Lee, J. Yoon, H. Lee, S. Park, and J. Lee Control of Rapsyn Stability by the CUL-3-containing E3 Ligase Complex J. Biol. Chem., March 20, 2009; 284(12): 8195 - 8206. [Abstract] [Full Text] [PDF]

				E. G. Bruneau, J. A. Esteban, and M. Akaaboune Receptor-associated proteins and synaptic plasticity FASEB J, March 1, 2009; 23(3): 679 - 688. [Abstract] [Full Text] [PDF]

				L. S. Borges, S. Yechikhov, Y. I. Lee, J. B. Rudell, M. B. Friese, S. J. Burden, and M. J. Ferns Identification of a Motif in the Acetylcholine Receptor {beta} Subunit Whose Phosphorylation Regulates Rapsyn Association and Postsynaptic Receptor Localization J. Neurosci., November 5, 2008; 28(45): 11468 - 11476. [Abstract] [Full Text] [PDF]