Interaction of cartilage matrix protein with aggrecan. Increased covalent cross-linking with tissue maturation

Research output: Contribution to journalArticle

Abstract

Cartilage matrix protein (CMP) is a trimeric protein present in many types of cartilage extracellular matrix. It has recently been purified under native conditions that allowed the proposal of a structural model (Hauser, N., and Paulsson, M. (1994) J. Biol. Chem. 269, 25747-25753). To examine the functional properties of CMP we studied its interaction with aggrecan within cartilage extracellular matrix. Aggrecan-enriched fractions were purified from bovine tracheal cartilage of different ages under nondenaturing and denaturing conditions, respectively, and characterized by a combination of biochemical methods and electron microscopy. The fractions contained a pool of CMP noncovalently associated with aggrecan as well as a pool of CMP that appears covalently cross-linked to the aggrecan core protein. Only about two thirds of the CMP subunits could be released even upon reduction under denaturing conditions. It appears that CMP is attached by a nonreducible covalent interaction of one of its subunits with the protein core. The amount of CMP strongly bound to aggrecan increases with age. Electron microscopy revealed interaction sites for CMP in the extended chondroitin-sulfate attachment domain E2. In old tissue five distinct binding sites for CMP were found while in young cartilage only three of these were occupied. The extent of decoration of E2 with CMP increases with age.

Details

Authors
  • Nik Hauser
  • Mats Paulsson
  • Dick Heinegård
  • Matthias Mörgelin
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Rheumatology and Autoimmunity
  • Infectious Medicine
Original languageEnglish
Pages (from-to)32247-32252
JournalJournal of Biological Chemistry
Volume271
Issue number50
Publication statusPublished - 1996
Publication categoryResearch
Peer-reviewedYes

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Connective Tissue Biology (013230151), Division of Infection Medicine (BMC) (013024020)