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Identification of the beta-dystroglycan binding epitope within the C-terminal region of alpha-dystroglycan

Sciandra, Francesca; Schneider, Martina LU ; Giardina, Bruno; Baumgartner, Stefan LU ; Petrucci, Tamara C. and Brancaccio, Andrea (2001) In European Journal of Biochemistry 268(16). p.4590-4597
Abstract
Dystroglycan is a receptor for extracellular matrix proteins that plays a crucial role during embryogenesis in addition to adult tissue stabilization. A precursor product of a single gene is post-translationally cleaved to form two different subunits, alpha and beta. The extracellular alpha-dystroglycan is a membrane-associated, highly glycosylated protein that binds to various extracellular matrix molecules, whereas the transmembrane beta-dystroglycan binds, via its cytosolic domain, to dystrophin and many other proteins. alpha- and beta-Dystroglycan interact tightly but noncovalently. We have previously shown that the N-terminal region of beta-dystroglycan, beta-DG(654-750), binds to the C-terminal region of murine alpha-dystroglycan... (More)
Dystroglycan is a receptor for extracellular matrix proteins that plays a crucial role during embryogenesis in addition to adult tissue stabilization. A precursor product of a single gene is post-translationally cleaved to form two different subunits, alpha and beta. The extracellular alpha-dystroglycan is a membrane-associated, highly glycosylated protein that binds to various extracellular matrix molecules, whereas the transmembrane beta-dystroglycan binds, via its cytosolic domain, to dystrophin and many other proteins. alpha- and beta-Dystroglycan interact tightly but noncovalently. We have previously shown that the N-terminal region of beta-dystroglycan, beta-DG(654-750), binds to the C-terminal region of murine alpha-dystroglycan independently from glycosylation. Preparing a series of deleted recombinant fragments and using solid-phase binding assays, the C-terminal sequence of alpha-dystroglycan containing the binding epitope for beta-dystroglycan has been defined more precisely. We found that a region of 36 amino acids, from position 550-585, is required for binding the extracellular region, amino acids 654-750 of beta-dystroglycan. Recently, a dystroglycan-like gene was identified in Drosophila that showed a moderate degree of conservation with vertebrate dystroglycan (31% identity, 48% similarity). Surprisingly, the Drosophila sequence contains a region showing a higher degree of identity and conservation (45% and 66%) that coincides with the 550-585 sequence of vertebrate alpha-dystroglycan. We have expressed this Drosophila dystroglycan fragment and measured its binding to the extracellular region of vertebrate (murine) beta-dystroglycan (Kd = 6 +/- 1 microM). These data confirm the proper identification of the beta-dystroglycan binding epitope and stress the importance of this region during evolution. This finding might help the rational design of dystroglycan-specific binding drugs, that could have important biomedical applications. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
recombinant proteins, deletion mapping, protein–protein interaction, solid-phase binding assay, sequence alignment
in
European Journal of Biochemistry
volume
268
issue
16
pages
4590 - 4597
publisher
Wiley-Blackwell
external identifiers
  • pmid:11502221
  • scopus:0034832747
ISSN
0014-2956
DOI
10.1046/j.1432-1327.2001.02386.x
language
English
LU publication?
yes
id
ace2ecdb-2a1d-46a0-81cb-d81f998b17c8 (old id 1121962)
date added to LUP
2008-07-14 11:11:00
date last changed
2018-06-24 04:36:22
@article{ace2ecdb-2a1d-46a0-81cb-d81f998b17c8,
  abstract     = {Dystroglycan is a receptor for extracellular matrix proteins that plays a crucial role during embryogenesis in addition to adult tissue stabilization. A precursor product of a single gene is post-translationally cleaved to form two different subunits, alpha and beta. The extracellular alpha-dystroglycan is a membrane-associated, highly glycosylated protein that binds to various extracellular matrix molecules, whereas the transmembrane beta-dystroglycan binds, via its cytosolic domain, to dystrophin and many other proteins. alpha- and beta-Dystroglycan interact tightly but noncovalently. We have previously shown that the N-terminal region of beta-dystroglycan, beta-DG(654-750), binds to the C-terminal region of murine alpha-dystroglycan independently from glycosylation. Preparing a series of deleted recombinant fragments and using solid-phase binding assays, the C-terminal sequence of alpha-dystroglycan containing the binding epitope for beta-dystroglycan has been defined more precisely. We found that a region of 36 amino acids, from position 550-585, is required for binding the extracellular region, amino acids 654-750 of beta-dystroglycan. Recently, a dystroglycan-like gene was identified in Drosophila that showed a moderate degree of conservation with vertebrate dystroglycan (31% identity, 48% similarity). Surprisingly, the Drosophila sequence contains a region showing a higher degree of identity and conservation (45% and 66%) that coincides with the 550-585 sequence of vertebrate alpha-dystroglycan. We have expressed this Drosophila dystroglycan fragment and measured its binding to the extracellular region of vertebrate (murine) beta-dystroglycan (Kd = 6 +/- 1 microM). These data confirm the proper identification of the beta-dystroglycan binding epitope and stress the importance of this region during evolution. This finding might help the rational design of dystroglycan-specific binding drugs, that could have important biomedical applications.},
  author       = {Sciandra, Francesca and Schneider, Martina and Giardina, Bruno and Baumgartner, Stefan and Petrucci, Tamara C. and Brancaccio, Andrea},
  issn         = {0014-2956},
  keyword      = {recombinant proteins,deletion mapping,protein–protein interaction,solid-phase binding assay,sequence alignment},
  language     = {eng},
  number       = {16},
  pages        = {4590--4597},
  publisher    = {Wiley-Blackwell},
  series       = {European Journal of Biochemistry},
  title        = {Identification of the beta-dystroglycan binding epitope within the C-terminal region of alpha-dystroglycan},
  url          = {http://dx.doi.org/10.1046/j.1432-1327.2001.02386.x},
  volume       = {268},
  year         = {2001},
}