Related Experiment Videos
The collagen receptor alpha 2 beta 1, from MG-63 and HT1080 cells, interacts with a cyclic RGD peptide
P M Cardarelli1, S Yamagata, I Taguchi
1Tanabe Research Laboratories, San Diego, California 92121.
The Journal of Biological Chemistry
|November 15, 1992
Summary
This study shows that the arginine-glycine-aspartic acid (RGD) sequence can bind to the collagen receptor alpha 2 beta 1. Cyclic RGD peptides demonstrated higher avidity for this collagen receptor.
Area of Science:
- Cell Biology
- Biochemistry
- Integrin Signaling
Background:
- Integrins are cell surface receptors that mediate cell adhesion to extracellular matrix (ECM) proteins.
- The arginine-glycine-aspartic acid (RGD) motif is a known recognition site for several integrins, notably the fibronectin receptor (alpha 5 beta 1).
- The interaction of collagen receptors with the RGD motif remained largely uncharacterized.
Purpose of the Study:
- To investigate whether collagen receptors interact with the RGD sequence.
- To determine if the alpha 2 beta 1 integrin, a known collagen receptor, binds to RGD-containing peptides.
Main Methods:
- Utilized an osteosarcoma cell line (MG-63) to assess adhesion to immobilized collagen I.
- Employed cyclic and linear RGD-containing peptides, as well as a non-RGD control peptide, to inhibit cell adhesion.
- Performed collagen-Sepharose affinity chromatography to isolate interacting proteins.
- Used immunoprecipitation with specific monoclonal antibodies to identify the eluted protein.
Main Results:
- Adhesion of MG-63 cells to collagen I was significantly inhibited by a cyclic RGD peptide (C*GRGDSPC*).
- Linear GRGDSP and a non-RGD cyclic peptide did not inhibit collagen adhesion.
- Collagen-Sepharose affinity chromatography eluted a heterodimeric protein that specifically bound to the cyclic RGD peptide.
- Immunoprecipitation confirmed the eluted protein as the alpha 2 beta 1 integrin, not alpha 3 beta 1.
- Cyclic RGD peptides exhibited higher avidity for the alpha 2 beta 1 collagen receptor compared to linear RGD peptides.
Conclusions:
- The arginine-glycine-aspartic acid (RGD) recognition sequence can interact with the alpha 2 beta 1 collagen receptor.
- The cyclic conformation of the RGD peptide enhances its binding avidity to alpha 2 beta 1.
- These findings provide evidence that the RGD motif may mediate collagen interaction with the alpha 2 beta 1 integrin.