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Ligand Nano-cluster Arrays in a Supported Lipid Bilayer
Published on: April 23, 2017
A novel ligand for CD44 is sulfated proteoglycan
N Toyama-Sorimachi1, M Miyasaka
1Department of Immunology, Tokyo Metropolitan Institute of Medical Science, Japan.
International Immunology
|April 1, 1994
Summary
Researchers identified a new CD44 ligand, gp600, involved in cell aggregation. This molecule, a chondroitin sulfate proteoglycan, binds CD44 independently of hyaluronan, suggesting a novel mechanism for CD44-mediated cell interactions.
Area of Science:
- Cell Biology
- Glycobiology
- Immunology
Background:
- CD44 is a cell surface glycoprotein crucial for tumor metastasis, lymphocyte differentiation, and homing.
- Its known ligand, hyaluronan, plays a significant role in these processes.
- However, the existence of other CD44 ligands has been hypothesized.
Purpose of the Study:
- To identify novel ligands for CD44.
- To investigate the role of these ligands in CD44-mediated cell aggregation.
- To characterize the nature of the interaction between CD44 and its newly identified ligand.
Main Methods:
- Transfection of mouse T cell line CTLL-2 with CD44 cDNA.
- Induction and observation of cell aggregation.
- Inhibition studies using anti-CD44 monoclonal antibody and hyaluronidase.
- Immunoprecipitation using a CD44-Ig chimeric molecule.
- Radiolabeling and enzymatic treatment (chondroitinase) of the ligand.
- In vitro binding assays with purified glycosaminoglycans.
Main Results:
- CD44-transfected cells exhibited CD44-dependent aggregation, blocked by anti-CD44 mAb but not hyaluronidase.
- Culture supernatants contained a molecule (gp600) that induced CD44-dependent aggregation.
- Immunoprecipitation identified gp600 as a macromolecule specifically binding to CD44.
- gp600 is a proteoglycan containing chondroitin sulfate, with a core protein.
- CD44 did not bind to purified chondroitin sulfates or dermatan sulfate in vitro.
Conclusions:
- A novel CD44 ligand, gp600, a chondroitin sulfate proteoglycan, has been identified.
- This ligand mediates CD44-dependent cell aggregation independently of hyaluronan.
- CD44 recognition may require the glycosaminoglycan to be associated with its core protein, or involve a novel type of chondroitin sulfate.
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