Biochemical Characterization of the Epithelial Dystroglycan Complex*
- From the Howard Hughes Medical Institute, Department of Physiology and Biophysics, Department of Neurology, University of Iowa College of Medicine, Iowa City, Iowa 52242
Abstract
Dystroglycan is a widely expressed extracellular matrix receptor that plays a critical role in basement membrane formation, epithelial development, and synaptogenesis. Dystroglycan was originally characterized in skeletal muscle as an integral component of the dystrophin glycoprotein complex, which is critical for muscle cell viability. Although the dystroglycan complex has been well characterized in skeletal muscle, there is little information on the structural composition of the dystroglycan complex outside skeletal muscle. Here we have biochemically characterized the dystroglycan complex in lung and kidney. We demonstrate that the presence of sarcoglycans and sarcospan in lung reflects association with dystroglycan in the smooth muscle. The smooth muscle dystroglycan complex in lung, composed of dystroglycan, dystrophin/utrophin, β-, δ-, ε-sarcoglycan, and sarcospan, can be biochemically separated from epithelial dystroglycan, which is not associated with any of the known sarcoglycans or sarcospan. Similarly, dystroglycan in kidney epithelial cells is not associated with any of the sarcoglycans or sarcospan. Thus, our data demonstrate that there are distinct dystroglycan complexes in non-skeletal muscle organs as follows: one from smooth muscle, which is associated with sarcoglycans forming a similar complex as in skeletal muscle, and one from epithelial cells.
Footnotes
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↵* This work was supported in part by the Muscular Dystrophy Association (to K. P. C.).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵‡ Supported by a postdoctoral fellowship from STINT.
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↵§ Investigator of the Howard Hughes Medical Institute. To whom correspondence should be addressed: Howard Hughes Medical Institute, University of Iowa College of Medicine, 400 EMRB, Iowa City, IA 52242. Tel.: 319-335-7867; Fax: 319-335-6957; E-mail: kevin-campbell@uiowa.edu.
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↵1 V. Straub and K. P. Campbell, unpublished data.
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↵3 M. Durbeej, D. Jung, and K. P. Campbell, unpublished data.
- Abbreviations:
- kb
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kilobase pair
- PAGE
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polyacrylamide gel electrophoresis
- WGA
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wheat germ agglutinin
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- Received May 4, 1999.
- Revision received June 22, 1999.
- The American Society for Biochemistry and Molecular Biology, Inc.
