| Autor: |
BURTON-WURSTER, Nancy, GENDELMAN, Rina, CHEN, Hao, GU, Da-Nian, TETREAULT, Jonathan W., LUST, George, SCHWARZBAUER, Jean E., MACLEOD, James N. |
| Zdroj: |
Biochemical Journal; August 1999, Vol. 341 Issue: 3 p555-561, 7p |
| Abstrakt: |
Fibronectin is an extracellular-matrix glycoprotein encoded by a single gene, but with significant protein heterogeneity introduced through alternative RNA splicing and post-translational modifications. The (V+C)- splice variant, in which nucleotides encoding protein segments III-15 and I-10 are deleted along with the entire variable region, is unique in that expression is restricted to cartilaginous tissues. All known fibronectin splice variants retain the two C-terminal cysteine residues essential for dimerization, but cellular and/or structural constraints appear to influence homo- and heterodimerization patterns. Dimerization patterns of the (V+C)- isoform were studied under native conditions within canine articular cartilage and experimentally in COS-7, NIH-3T3 and CHO-K1 cell cultures. In all systems, (V+C)- fibronectin secretion was predominantly in a homodimeric configuration. Lower levels of (V+C)- monomers were also present. Heterodimers of (V+C)- with V+,C+ (V120) isoforms were not detected. Heterodimers of (V+C)- with V-,C+ (V0) subunits were detected only at low levels. Functional properties may differ significantly among monomers, homodimers and heterodimers. The unique dimerization pattern of (V+C)- fibronectin is consistent with this isoform having specialized functional properties in situ that are important for either the structural organization and biomechanical properties of cartilage matrix or regulation of a chondrocytic phenotype. |
| Databáze: |
Supplemental Index |
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