Molecular organization at the glycoprotein‐complex‐binding site of dystrophin

Abstract

Direct interaction between the C‐terminal portion of dystrophin and dystrophin‐associated proteins was investigated. The binding of dystrophin to each protein was reconstituted by overlaying bacterially expressed dystrophin fusion proteins onto the blot membranes to which dystrophin‐associated proteins were transferred after separation by SDS/PAGE with the following results. (a) Among the components of the glycoprotein complex which links dystrophin to the sarcolemma, a 43‐kDa dystrophin‐associated glycoprotein binds directly to dystrophin. Although at least one of the binding sites of this protein resides within the cysteine‐rich domain of dystrophin, a contribution of additional amino acid residues within the first half of the C‐terminal domain was also suggested for more secure binding. (b) Two other proteins also directly bind to dystrophin. Their binding sites are suggested to reside within the last half of the C‐terminal domain which is alternatively spliced depending on the tissue type. Previously, based on the enzyme digestion experiments, we showed that the binding site for the glycoprotein complex on dystrophin is present within the cysteine‐rich domain and the first half of the C‐terminal domain [Suzuki, A., Yoshida, M., Yamamoto, H. & Ozawa, E. (1992) FEBS Lett. 308, 154–160]. Here, we have extended this work and found that the region which is involved in interaction with the complex is widely extended to the entire length of this part of the molecule. On the basis of the present results, we propose a model of molecular architecture at the binding site for the complex on dystrophin.

Direct binding of Torpedo syntrophin to dystrophin and the 87 kDa dystrophin homologue

“…Blot overlay analysis was done using a modified method of Suzuki et al [23]. Purified dystrophin complex or bacteria containing expressed fusion proteins were separated on an 8% SDS-PAGE gel and blotted to nitrocellulose as described previously [10].…”

Genetic Background Affects Properties of Satellite Cells and mdx Phenotypes

“…1 The dystrophin gene encodes a 427-kDa cytoskeletal protein that forms the dystrophin/glycoprotein complex at the sarcolemma with ␣-and ␤-dystroglycans, ␣-, ␤-, ␥-, and ␦-sarcoglycans, and other molecules, and links the cytoskeleton of myofibers to the extracellular matrix in skeletal muscle. 2,3 The lack of dystrophin in the sarcolemma disturbs the assembly of the dystrophin/glycoprotein complex and causes instability of the muscle membrane, leading to muscle degeneration and myofiber loss. The histopathological hallmarks of DMD include degeneration, necrosis, accumulation of fat and fibrosis, and insufficient regeneration of myofibers accompanied by a loss of myofibers.…”

Inhibition of agrin‐mediated acetylcholine receptor clustering by utrophin C‐terminal peptides

“…(B) Detail of the domain organization of the carboxyl terminus of utrophin and the structure of the constructs used. Regions that bind P-dystrophin and syntrophins are indicated according to Suzuki et al (1994Suzuki et al ( , 1995. Cys rich; cysteine rich domain, FHC; first halfof C-terminal domain, LHC; last halfof C-terminal domain.…”