201. Localization of the dystrophin binding site at the carboxyl terminus of beta-dystroglycan.
- Author
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Rosa G, Ceccarini M, Cavaldesi M, Zini M, and Petrucci TC
- Subjects
- Animals, Apoproteins metabolism, Base Sequence, Binding Sites, Cytoskeletal Proteins chemistry, Cytoskeletal Proteins isolation & purification, DNA Primers, Dystroglycans, Glutathione Transferase biosynthesis, Macromolecular Substances, Membrane Glycoproteins chemistry, Membrane Glycoproteins isolation & purification, Molecular Sequence Data, Muscle, Skeletal metabolism, Mutagenesis, Polymerase Chain Reaction, Rabbits, Recombinant Fusion Proteins biosynthesis, Recombinant Proteins chemistry, Recombinant Proteins isolation & purification, Recombinant Proteins metabolism, Sequence Deletion, Brain metabolism, Cytoskeletal Proteins metabolism, Dystrophin metabolism, Membrane Glycoproteins metabolism
- Abstract
Alpha- and beta-dystroglycan form a heteromeric transmembrane complex linking the extracellular matrix to the cytoskeleton. In muscle beta-dystroglycan interacts with dystrophin on the inside of the cell and with alpha-dystroglycan, which binds the extracellular matrix protein laminin, on the outside. Dystroglycan is expressed not only in muscle but also in other tissues. We cloned beta-dystroglycan from rabbit brain by RT-PCR and expressed deletion mutants of the beta-dystroglycan cytoplasmic domain as GST-fusion proteins. We identified the dystrophin binding region on beta-dystroglycan by protein overlay and co-precipitation assays with skeletal muscle dystrophin and recombinant apo-dystrophin I. We demonstrate that the beta-dystroglycan carboxyl terminus interacts with dystrophin and that the binding site is restricted to the last 20 amino acids. Our data also suggest that the region adjacent to the beta-dystroglycan transmembrane domain might modulate beta-dystroglycan-dystrophin interaction.
- Published
- 1996
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