Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/5658
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Type: Journal article
Title: Molecular interactions of biglycan and decorin with elastic fiber components - Biglycan forms a ternary complex with tropoelastin and microfibril-associated glycoprotein
Author: Reinboth, B.
Hanssen, E.
Cleary, E.
Gibson, M.
Citation: Journal of Biological Chemistry, 2002; 277(6):3950-3957
Publisher: Amer Soc Biochemistry Molecular Biology Inc
Issue Date: 2002
ISSN: 0021-9258
1083-351X
Statement of
Responsibility: 
Betty Reinboth, Eric Hanssen, Edward G. Cleary and Mark A. Gibson
Abstract: The interactions of the dermatan sulfate proteoglycans biglycan and decorin have been investigated with the elastic fiber components, tropoelastin, fibrillin-containing microfibrils, and microfibril-associated glycoproteins (MAGP) 1 and 2. Both proteoglycans were found to bind tropoelastin and fibrillin-containing microfibrils but not MAGPs 1 and 2 in solid phase binding assays. The specificity of the binding of biglycan and decorin to tropoelastin was confirmed by co-immunoprecipitation experiments and by the blocking of the interactions with elastin-derived peptides. Isolated core proteins from biglycan and decorin bound to tropoelastin more strongly than the intact proteoglycans, and there were no differences in the tropoelastin binding characteristics of distinct glucuronate-rich and iduronate-rich glycoforms of biglycan. These findings indicated that the binding sites were contained in the protein cores of the proteoglycans rather than the glycosaminoglycan side chains. Scatchard analysis showed that biglycan bound more avidly than decorin to tropoelastin with Kd values estimated as 1.95 × 107 M and 5.3 × 107 M, respectively. In blocking experiments each proteoglycan showed extensive inhibition of binding of the other to tropoelastin but was most effective at blocking its own binding. This result suggested that biglycan and decorin had closely spaced but distinct binding sites on tropoelastin. Addition of the elastin-binding protein MAGP-1 to the assays enhanced the binding of biglycan to tropoelastin but had no effect on the decorin-tropoelastin interaction. Co-immunoprecipitation experiments showed that MAGP-1 interacted with biglycan but not decorin in the solution phase. The results indicated that biglycan specifically formed a ternary complex with tropoelastin and MAGP-1. Overall the study supports the concept that biglycan may have a specific role in the elastinogenic phase of elastic fiber formation.
Keywords: Microfilament Proteins; Glycoproteins; Proteoglycans; Contractile Proteins; Tropoelastin; Extracellular Matrix Proteins; Protein Binding; Decorin; Biglycan; Fibrillins
Description: © American Society for Biochemistry and Molecular Biology
RMID: 0020020621
DOI: 10.1074/jbc.M109540200
Published version: http://www.jbc.org/cgi/content/abstract/277/6/3950
Appears in Collections:Pathology publications

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