Recombinant expression and characterization of a novel fibronectin isoform expressed in cartilaginous tissues.
A novel fibronectin (FN) isoform lacking the segment from IIICS (type III connecting segment) through the I-10 module is expressed predominantly in normal cartilaginous tissues. We expressed and purified recombinant cartilage-type FN using a mammalian expression system and characterized its molecular and biological properties. Although FNs have been shown to be secreted as disulfide-bonded dimers, cartilage-type FN was secreted mainly as a monomer. It was less potent than plasma-type FN in promoting cell adhesion and binding to integrin alpha5beta1, although it was more active than plasma-type FN in binding to chondroitin sulfate E. When added exogenously, cartilage-type FN was poorly assembled into the fibrillar FN matrix, mostly because of its monomeric structure. Given that cartilage is characterized by its non-fibrillar matrix with abundant chondroitin sulfate-containing proteoglycans, it is likely that cartilage-type FN has evolved to adapt itself to the non-fibrillar structure of the cartilage matrix through acquisition of a novel mechanism of alternative pre-mRNA splicing.
Kozaki
Tomohiro
T
Division of Protein Chemistry, Institute for Protein Research, Graduate School of Medicine, Osaka University, Suita, Japan.
Matsui
Yoshito
Y
Gu
Jianguo
J
Nishiuchi
Ryoko
R
Sugiura
Nobuo
N
Kimata
Koji
K
Ozono
Keiichi
K
Yoshikawa
Hideki
H
Sekiguchi
Kiyotoshi
K
D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D016466:CHO Cells; D002356:Cartilage / Q000378:metabolism*; D002448:Cell Adhesion; D002460:Cell Line; D002478:Cells, Cultured; D002809:Chondroitin Sulfates / Q000737:chemistry; D006224:Cricetinae; D018076:DNA, Complementary / Q000378:metabolism; D004220:Disulfides / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005353:Fibronectins / Q000096:biosynthesis* / Q000737:chemistry*; D019084:Fluorescent Antibody Technique, Indirect; D006025:Glycosaminoglycans / Q000378:metabolism; D006493:Heparin / Q000378:metabolism; D015151:Immunoblotting; D039081:Integrin alpha5beta1 / Q000378:metabolism; D051379:Mice; D008957:Models, Genetic; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D020033:Protein Isoforms; D011509:Proteoglycans / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D012326:RNA Splicing; D011994:Recombinant Proteins / Q000737:chemistry; D014162:Transfection
D000911:Antibodies, Monoclonal; D018076:DNA, Complementary; D004220:Disulfides; D005353:Fibronectins; D006025:Glycosaminoglycans; D039081:Integrin alpha5beta1; D010455:Peptides; D020033:Protein Isoforms; D011509:Proteoglycans; D011994:Recombinant Proteins; D012313:RNA; D006493:Heparin; D002809:Chondroitin Sulfates