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Syndecan binding sites in the laminin alpha1 chain G domain.
- Source :
-
Biochemistry [Biochemistry] 2003 Nov 04; Vol. 42 (43), pp. 12625-33. - Publication Year :
- 2003
-
Abstract
- The laminin alpha1 chain G domain has multiple biological activities. Previously, we identified cell binding sequences in the laminin alpha1 chain G domain by screening 113 synthetic peptide-polystyrene beads for cell attachment activity. Here, we have used a recombinant protein of the laminin alpha1 G domain (rec-alpha1G) and a large set of synthetic peptides to further identify and characterize heparin, cell, and syndecan-4 binding sites in the laminin alpha1 chain G domain. The rec-alpha1G protein promoted both cell attachment and heparin binding (K(D) = 19 nM). Cell attachment to the rec-alpha1G protein was inhibited 60% by heparin and 30% by EDTA. The heparin binding sites were identified by competing heparin binding to the rec-alpha1G protein with 110 synthetic peptides in solution. Only two peptides, AG73 (IC(50) = 147 microM) and AG75 (IC(50) = 206 microM), inhibited heparin binding to rec-alpha1G. When the peptides were compared in a solid-phase heparin binding assay, AG73 showed more heparin binding than AG75. AG73 also inhibited fibroblast attachment to the rec-alpha1G protein, but AG75 did not. Cell attachment to the peptides was studied using peptide-coated plates and peptide-conjugated sepharose beads. AG73 promoted cell attachment in both assays, but AG75 only showed cell attachment activity in the bead assay. Additionally, AG73, but not AG75, inhibited branching morphogenesis of mouse submandibular glands in organ culture. Furthermore, the rec-alpha1G protein bound syndecan-4, and both AG73 and AG75 inhibited this binding. These results suggest that the AG73 and AG75 sites are important for heparin and syndecan-4 binding in the laminin alpha1 chain G domain. These sites may play a critical role in the diverse biological activities involving heparin and syndecan-4 binding.
- Subjects :
- Amino Acid Sequence
Animals
Binding Sites
CHO Cells
Cell Adhesion
Cells, Cultured
Cricetinae
Heparin metabolism
Humans
In Vitro Techniques
Laminin chemistry
Membrane Glycoproteins chemistry
Mice
Molecular Sequence Data
Peptides pharmacology
Protein Binding
Proteoglycans chemistry
Submandibular Gland drug effects
Submandibular Gland growth & development
Syndecans
Laminin metabolism
Membrane Glycoproteins metabolism
Proteoglycans metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0006-2960
- Volume :
- 42
- Issue :
- 43
- Database :
- MEDLINE
- Journal :
- Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 14580209
- Full Text :
- https://doi.org/10.1021/bi030014s