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Multiple functions of the von Willebrand Factor A domain in matrilins: secretion, assembly, and proteolysis

Authors :
Kanbe Katsuaki
Chen Qian
Luo Jun-ming
Wang Zheng-ke
Zhang Yue
Source :
Journal of Orthopaedic Surgery and Research, Vol 3, Iss 1, p 21 (2008)
Publication Year :
2008
Publisher :
BMC, 2008.

Abstract

Abstract The von Willebrand Factor A (vWF A) domain is one of the most widely distributed structural modules in cell-matrix adhesive molecules such as intergrins and extracellular matrix proteins. Mutations in the vWF A domain of matrilin-3 cause multiple epiphyseal dysplasia (MED), however the pathological mechanism remains to be determined. Previously we showed that the vWF A domain in matrilin-1 mediates formation of a filamentous matrix network through metal-ion dependent adhesion sites in the domain. Here we show two new functions of the vWF A domain in cartilage-specific matrilins (1 and 3). First, vWF A domain regulates oligomerization of matrilins. Insertion of a vWF A domain into matrilin-3 converts the formation of a mixture of matrilin-3 tetramer, trimer, and dimer into a tetramer only, while deletion of a vWF A domain from matrilin-1 converts the formation of the native matrilin-1 trimer into a mixture of trimer and dimer. Second, the vWF A domain protects matrilin-1 from proteolysis. We identified a latent proteolytic site next to the vWF A2 domain in matrilin-1, which is sensitive to the inhibitors of matrix proteases. Deletion of the abutting vWF A domain results in degradation of matrilin-1, presumably by exposing the adjacent proteolytic site. In addition, we also confirmed the vWF A domain is vital for the secretion of matrilin-3. Secretion of the mutant matrilin-3 harbouring a point mutation within the vWF A domain, as occurred in MED patients, is markedly reduced and delayed, resulting from intracellular retention of the mutant matrilin-3. Taken together, our data suggest that different mutations/deletions of the vWF A domain in matrilins may lead to distinct pathological mechanisms due to the multiple functions of the vWF A domain.

Details

Language :
English
ISSN :
1749799X
Volume :
3
Issue :
1
Database :
Directory of Open Access Journals
Journal :
Journal of Orthopaedic Surgery and Research
Publication Type :
Academic Journal
Accession number :
edsdoj.4c3fb5f9ff174b2986815fd2eb9ca9fa
Document Type :
article
Full Text :
https://doi.org/10.1186/1749-799X-3-21