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Cartilage oligomeric matrix protein forms protein complexes with synovial lubricin via non-covalent and covalent interactions

Flowers, S. A.; Kalamajski, Sebastian LU ; Ali, Leena; Björkman, L. I.; Raj, J. R.; Aspberg, A. LU ; Karlsson, Niclas G and Jin, C. (2017) In Osteoarthritis and Cartilage 25(9). p.1496-1504
Abstract

Objective: Understanding the cartilage surface structure, lost in arthritic disease, is essential for developing strategies to effectively restore it. Given that adherence of the lubricating protein, lubricin, to the cartilage surface is critical for boundary lubrication, an interaction with cartilage oligomeric matrix protein (COMP) was investigated. COMP, an abundant cartilage protein, is known to be important for matrix formation. Design: Synovial fluid (SF) from arthritic patients was used to detect possible COMP-lubricin complexes by immunological methods. Recombinant (RC) COMP and lubricin fragments were expressed to characterize this bonding and mass spectrometry employed to specifically identify the cysteines involved in... (More)

Objective: Understanding the cartilage surface structure, lost in arthritic disease, is essential for developing strategies to effectively restore it. Given that adherence of the lubricating protein, lubricin, to the cartilage surface is critical for boundary lubrication, an interaction with cartilage oligomeric matrix protein (COMP) was investigated. COMP, an abundant cartilage protein, is known to be important for matrix formation. Design: Synovial fluid (SF) from arthritic patients was used to detect possible COMP-lubricin complexes by immunological methods. Recombinant (RC) COMP and lubricin fragments were expressed to characterize this bonding and mass spectrometry employed to specifically identify the cysteines involved in inter-protein disulfide bonds. Results: COMP-lubricin complexes were identified in the SF of arthritic patients by Western blot, co-immunoprecipitation and sandwich ELISA. RC fragment solid-phase binding assays showed that the C-terminal (amino acids (AA) 518-757) of COMP bound non-covalently to the N-terminal of lubricin (AA 105-202). Mass spectrometry determined that although cysteines throughout COMP were involved in binding with lubricin, the cysteines in lubricin were primarily focused to an N-terminal region (AA 64-86). The close proximity of the non-covalent and disulfide binding domains on lubricin suggest a two-step mechanism to strongly bind lubricin to COMP. Conclusion: These data demonstrate that lubricin forms a complex network with COMP involving both non-covalent and covalent bonds. This complex between lubricin and the cartilage protein COMP can be identified in the SF of patients with arthritis conditions including osteoarthritis (OA) and rheumatoid arthritis (RA).

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Boundary lubrication, Cartilage degradation, Cartilage oligomeric matrix protein, Lubricin, O-linked glycoproteins, Proteomics
in
Osteoarthritis and Cartilage
volume
25
issue
9
pages
1496 - 1504
publisher
Elsevier
external identifiers
  • scopus:85017472194
  • wos:000407934000016
ISSN
1063-4584
DOI
10.1016/j.joca.2017.03.016
language
English
LU publication?
yes
id
023e307b-a260-4bf4-a5b7-eb0913c1ed46
date added to LUP
2017-05-02 14:48:27
date last changed
2017-09-18 13:33:45
@article{023e307b-a260-4bf4-a5b7-eb0913c1ed46,
  abstract     = {<p>Objective: Understanding the cartilage surface structure, lost in arthritic disease, is essential for developing strategies to effectively restore it. Given that adherence of the lubricating protein, lubricin, to the cartilage surface is critical for boundary lubrication, an interaction with cartilage oligomeric matrix protein (COMP) was investigated. COMP, an abundant cartilage protein, is known to be important for matrix formation. Design: Synovial fluid (SF) from arthritic patients was used to detect possible COMP-lubricin complexes by immunological methods. Recombinant (RC) COMP and lubricin fragments were expressed to characterize this bonding and mass spectrometry employed to specifically identify the cysteines involved in inter-protein disulfide bonds. Results: COMP-lubricin complexes were identified in the SF of arthritic patients by Western blot, co-immunoprecipitation and sandwich ELISA. RC fragment solid-phase binding assays showed that the C-terminal (amino acids (AA) 518-757) of COMP bound non-covalently to the N-terminal of lubricin (AA 105-202). Mass spectrometry determined that although cysteines throughout COMP were involved in binding with lubricin, the cysteines in lubricin were primarily focused to an N-terminal region (AA 64-86). The close proximity of the non-covalent and disulfide binding domains on lubricin suggest a two-step mechanism to strongly bind lubricin to COMP. Conclusion: These data demonstrate that lubricin forms a complex network with COMP involving both non-covalent and covalent bonds. This complex between lubricin and the cartilage protein COMP can be identified in the SF of patients with arthritis conditions including osteoarthritis (OA) and rheumatoid arthritis (RA).</p>},
  author       = {Flowers, S. A. and Kalamajski, Sebastian and Ali, Leena and Björkman, L. I. and Raj, J. R. and Aspberg, A. and Karlsson, Niclas G and Jin, C.},
  issn         = {1063-4584},
  keyword      = {Boundary lubrication,Cartilage degradation,Cartilage oligomeric matrix protein,Lubricin,O-linked glycoproteins,Proteomics},
  language     = {eng},
  number       = {9},
  pages        = {1496--1504},
  publisher    = {Elsevier},
  series       = {Osteoarthritis and Cartilage},
  title        = {Cartilage oligomeric matrix protein forms protein complexes with synovial lubricin via non-covalent and covalent interactions},
  url          = {http://dx.doi.org/10.1016/j.joca.2017.03.016},
  volume       = {25},
  year         = {2017},
}