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Enhanced Activity of Transforming Growth Factor β1 (TGF-β1) Bound to Cartilage Oligomeric Matrix Protein
- Source :
- Journal of Biological Chemistry. 286:43250-43258
- Publication Year :
- 2011
- Publisher :
- Elsevier BV, 2011.
-
Abstract
- Cartilage oligomeric matrix protein (COMP) is an important non-collagenous cartilage protein that is essential for the structural integrity of the cartilage extracellular matrix. The repeated modular structure of COMP allows it to "bridge" and assemble multiple cartilage extracellular matrix components such as collagens, matrilins, and proteoglycans. With its modular structure, COMP also has the potential to act as a scaffold for growth factors, thereby affecting how and when the growth factors are presented to cell-surface receptors. However, it is not known whether COMP binds growth factors. We studied the binding interaction between COMP and TGF-β1 in vitro and determined the effect of COMP on TGF-β1-induced signal transduction in reporter cell lines and primary cells. Our results demonstrate that mature COMP protein binds to multiple TGF-β1 molecules and that the peak binding occurs at slightly acidic pH. These interactions were confirmed by dual polarization interferometry and visualized by rotary shadow electron microscopy. There is cation-independent binding of TGF-β1 to the C-terminal domain of COMP. In the presence of manganese, an additional TGF-β-binding site is present in the TSP3 repeats of COMP. Finally, we show that COMP-bound TGF-β1 causes increased TGF-β1-dependent transcription. We conclude that TGF-β1 binds to COMP and that TGF-β1 bound to COMP has enhanced bioactivity.
- Subjects :
- musculoskeletal diseases
animal structures
Enzyme-Linked Immunosorbent Assay
Cartilage Oligomeric Matrix Protein
Biochemistry
Cell Line
Transforming Growth Factor beta1
Extracellular matrix
fluids and secretions
Microscopy, Electron, Transmission
medicine
Humans
Matrilin Proteins
Receptor
Molecular Biology
Glycoproteins
Cartilage oligomeric matrix protein
Extracellular Matrix Proteins
biology
Reverse Transcriptase Polymerase Chain Reaction
Chemistry
Cartilage
Cell Biology
musculoskeletal system
In vitro
carbohydrates (lipids)
medicine.anatomical_structure
Cell culture
Bone Morphogenetic Proteins
biology.protein
Biophysics
Signal transduction
Protein Binding
Transforming growth factor
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 286
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....4740a55de1c20037167b80a0faca3976