Open AccessAssembly of collagen types II, IX and XI into nascent hetero‐fibrils by a rat chondrocyte cell line
Author(s) -
Fernandes Russell J.,
Schmid Thomas M.,
Eyre David R.
Publication year - 2003
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1033.2003.03711.x
Subject(s) - procollagen peptidase , fibril , extracellular matrix , chemistry , chondrocyte , cartilage , pyridinoline , biophysics , matrix (chemical analysis) , collagen, type i, alpha 1 , type ii collagen , type i collagen , biochemistry , anatomy , microbiology and biotechnology , biology , alkaline phosphatase , in vitro , chromatography , osteocalcin , enzyme , endocrinology
The cell line, RCS‐LTC (derived from the Swarm rat chondrosarcoma), deposits a copious extracellular matrix in which the collagen component is primarily a polymer of partially processed type II N‐procollagen molecules. Transmission electron microscopy of the matrix shows no obvious fibrils, only a mass of thin unbanded filaments. We have used this cell system to show that the type II N‐procollagen polymer nevertheless is stabilized by pyridinoline cross‐links at molecular sites (mediated by N‐ and C‐telopeptide domains) found in collagen II fibrils processed normally. Retention of the N‐propeptide therefore does not appear to interfere with the interactions needed to form cross‐links and mature them into trivalent pyridinoline residues. In addition, using antibodies that recognize specific cross‐linking domains, it was shown that types IX and XI collagens, also abundantly deposited into the matrix by this cell line, become covalently cross‐linked to the type II N‐procollagen. The results indicate that the assembly and intertype cross‐linking of the cartilage type II collagen heteropolymer is an integral, early process in fibril assembly and can occur efficiently prior to the removal of the collagen II N‐propeptides.