Structural and Functional Aspects of Dystroglycan During Agrin -Mediated Acetylcholine Receptor Clustering at the Mammalian Neuromuscular Junction

Prior studies on dystroglycan support dystroglycan as an agrin-binding protein. More specifically, data suggests that the carbohydrate residues on dystroglycan may be involved in binding to agrin. However, genetic and functional studies on dystroglycan's role in agrin-mediated acetylcholine receptor (AChR) clustering remain unclear. Evidence points toward an indirect role for dystroglycan, a role which is important for the aggregation and stabilization of micro-clusters. The question of what regions of dystroglycan are functionally important for its role in agrin-induced AChR clustering is still unanswered. In an attempt to answer this question, we created beta-dystroglycan deletion and point mutants, and expressed these mutants in C2 muscle cells. Next, we assayed transfected myotubes for their responsiveness to agrin by measuring the number of AChR clusters per myotube segment. Last, we characterized a previously unknown protein-lipid interaction for dystroglycan. Our results demonstrate that the cytoplasmic juxtamembrane region of beta-dystroglycan that consists of the amino acid sequence ICYRKKRKGK possesses an AChR cluster inhibitory activity. This inhibitory activity primarily depends on the charged basic amino acids. In addition, our results suggest that the juxtamembrane region has an affinity for phosphoinositides.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biochemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Kahl, Joanna Patrice

Contributors dc:contributor

• James T. Campanelli

• Biology, Cell

Language dc:language

eng

Identifier

(MiAaPQ)AAI3153337

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/84805